diff --git a/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/base.py.j2 b/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/base.py.j2
index fd7832ef81..d4364e44f3 100644
--- a/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/base.py.j2
+++ b/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/base.py.j2
@@ -103,6 +103,9 @@ class {{ service.name }}Transport(abc.ABC):
         # Save the scopes.
         self._scopes = scopes
 
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
+
         # If no credentials are provided, then determine the appropriate
         # defaults.
         if credentials and credentials_file:
@@ -114,7 +117,7 @@ class {{ service.name }}Transport(abc.ABC):
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
 
         # If the credentials are service account credentials, then always try to use self signed JWT.
diff --git a/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/grpc.py.j2 b/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/grpc.py.j2
index 9d4a91aa03..02d75444ff 100644
--- a/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/grpc.py.j2
+++ b/gapic/ads-templates/%namespace/%name/%version/%sub/services/%service/transports/grpc.py.j2
@@ -133,7 +133,8 @@ class {{ service.name }}GrpcTransport({{ service.name }}Transport):
 
         if channel:
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/base.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/base.py.j2
index 316eb84f96..fc4b16f6c8 100644
--- a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/base.py.j2
+++ b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/base.py.j2
@@ -107,6 +107,8 @@ class {{ service.name }}Transport(abc.ABC):
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -119,7 +121,7 @@ class {{ service.name }}Transport(abc.ABC):
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc.py.j2
index 268ea2ea5f..69b92f162e 100644
--- a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc.py.j2
+++ b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc.py.j2
@@ -137,7 +137,8 @@ class {{ service.name }}GrpcTransport({{ service.name }}Transport):
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_asyncio.py.j2 b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_asyncio.py.j2
index ab14820095..8a3bc140bc 100644
--- a/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_asyncio.py.j2
+++ b/gapic/templates/%namespace/%name_%version/%sub/services/%service/transports/grpc_asyncio.py.j2
@@ -183,7 +183,8 @@ class {{ service.grpc_asyncio_transport_name }}({{ service.name }}Transport):
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/gapic/templates/noxfile.py.j2 b/gapic/templates/noxfile.py.j2
index db66913351..271c722637 100644
--- a/gapic/templates/noxfile.py.j2
+++ b/gapic/templates/noxfile.py.j2
@@ -156,6 +156,8 @@ def mypy(session):
         'types-protobuf'
     )
     session.install('.')
+    # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+    session.install("google-api-core>=2.19.1rc0")
     session.run(
         'mypy',
         '-p',
diff --git a/gapic/utils/lines.py b/gapic/utils/lines.py
index fb24e19351..1a5b5ce8e3 100644
--- a/gapic/utils/lines.py
+++ b/gapic/utils/lines.py
@@ -191,7 +191,7 @@ def wrap(text: str, width: int, *, offset: Optional[int] = None, indent: int = 0
             break_long_words=False,
             initial_indent=' ' * indent,
             # ensure that subsequent lines for lists are indented 2 spaces
-            subsequent_indent=' ' * indent + \
+            subsequent_indent=' ' * indent +
             ' ' * get_subsequent_line_indentation_level(token.strip()),
             text=token,
             width=width,
diff --git a/noxfile.py b/noxfile.py
index 9eba5d7c79..41fec240bc 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -272,6 +272,9 @@ def showcase_library(
             # See https://github.com/googleapis/gapic-generator-python/issues/1788
             # Install the library without a constraints file.
             session.install("-e", tmp_dir)
+
+        # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+        session.install("google-api-core>=2.19.1rc0")
         yield tmp_dir
 
 
diff --git a/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/base.py b/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/base.py
index 5e4aa9aab8..40735ff6b5 100755
--- a/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/base.py
+++ b/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/base.py
@@ -83,6 +83,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -95,7 +97,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc.py b/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc.py
index a9862888e2..63790c16d1 100755
--- a/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc.py
+++ b/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc.py
@@ -123,7 +123,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc_asyncio.py b/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc_asyncio.py
index 46532f8549..2ff6022256 100755
--- a/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/asset/google/cloud/asset_v1/services/asset_service/transports/grpc_asyncio.py
@@ -169,7 +169,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/asset/noxfile.py b/tests/integration/goldens/asset/noxfile.py
index 0872592be3..383128c9f6 100755
--- a/tests/integration/goldens/asset/noxfile.py
+++ b/tests/integration/goldens/asset/noxfile.py
@@ -167,6 +167,8 @@ def mypy(session):
         'types-protobuf'
     )
     session.install('.')
+    # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+    session.install("google-api-core>=2.19.1rc0")
     session.run(
         'mypy',
         '-p',
diff --git a/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/base.py b/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/base.py
index 2f1aa66aac..1c7ac92800 100755
--- a/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/base.py
+++ b/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/base.py
@@ -80,6 +80,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -92,7 +94,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc.py b/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc.py
index d07061919a..b0dd5bb669 100755
--- a/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc.py
+++ b/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc.py
@@ -128,7 +128,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc_asyncio.py b/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc_asyncio.py
index 4a4809a095..447c2e3baf 100755
--- a/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/credentials/google/iam/credentials_v1/services/iam_credentials/transports/grpc_asyncio.py
@@ -174,7 +174,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/credentials/noxfile.py b/tests/integration/goldens/credentials/noxfile.py
index 93241d052f..bb492879f5 100755
--- a/tests/integration/goldens/credentials/noxfile.py
+++ b/tests/integration/goldens/credentials/noxfile.py
@@ -167,6 +167,8 @@ def mypy(session):
         'types-protobuf'
     )
     session.install('.')
+    # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+    session.install("google-api-core>=2.19.1rc0")
     session.run(
         'mypy',
         '-p',
diff --git a/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/base.py b/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/base.py
index 6113e4beaa..86ab6167d4 100755
--- a/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/base.py
+++ b/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/base.py
@@ -91,6 +91,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -103,7 +105,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc.py b/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc.py
index bf51d45946..54dc681435 100755
--- a/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc.py
+++ b/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc.py
@@ -133,7 +133,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc_asyncio.py b/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc_asyncio.py
index 271fbf8ada..864708c68f 100755
--- a/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/eventarc/google/cloud/eventarc_v1/services/eventarc/transports/grpc_asyncio.py
@@ -179,7 +179,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/eventarc/noxfile.py b/tests/integration/goldens/eventarc/noxfile.py
index 0e5ae5f086..6821d9d1b2 100755
--- a/tests/integration/goldens/eventarc/noxfile.py
+++ b/tests/integration/goldens/eventarc/noxfile.py
@@ -167,6 +167,8 @@ def mypy(session):
         'types-protobuf'
     )
     session.install('.')
+    # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+    session.install("google-api-core>=2.19.1rc0")
     session.run(
         'mypy',
         '-p',
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/base.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/base.py
index 9f1f2ab45f..26cbb2b350 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/base.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/base.py
@@ -86,6 +86,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -98,7 +100,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc.py
index 81818e1ca6..08c0c4707b 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc.py
@@ -123,7 +123,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc_asyncio.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc_asyncio.py
index 0a8dca763f..f804863e90 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/config_service_v2/transports/grpc_asyncio.py
@@ -169,7 +169,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/base.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/base.py
index c9850fac55..3ec63b6148 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/base.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/base.py
@@ -86,6 +86,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -98,7 +100,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc.py
index 87498f9bc1..aff5aad6e1 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc.py
@@ -121,7 +121,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc_asyncio.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc_asyncio.py
index 337b490b11..9817b9fd82 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/logging_service_v2/transports/grpc_asyncio.py
@@ -167,7 +167,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/base.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/base.py
index c347164816..941b7050f7 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/base.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/base.py
@@ -86,6 +86,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -98,7 +100,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc.py
index ffe49e97d4..04c8ab0512 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc.py
@@ -121,7 +121,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc_asyncio.py b/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc_asyncio.py
index 4715a47d0d..e5ff12d013 100755
--- a/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/logging/google/cloud/logging_v2/services/metrics_service_v2/transports/grpc_asyncio.py
@@ -167,7 +167,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/logging/noxfile.py b/tests/integration/goldens/logging/noxfile.py
index 0292d4feb3..54f31479ec 100755
--- a/tests/integration/goldens/logging/noxfile.py
+++ b/tests/integration/goldens/logging/noxfile.py
@@ -167,6 +167,8 @@ def mypy(session):
         'types-protobuf'
     )
     session.install('.')
+    # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+    session.install("google-api-core>=2.19.1rc0")
     session.run(
         'mypy',
         '-p',
diff --git a/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/base.py b/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/base.py
index 7c916ad9da..b8a9fa84b5 100755
--- a/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/base.py
+++ b/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/base.py
@@ -83,6 +83,8 @@ def __init__(
 
         # Save the scopes.
         self._scopes = scopes
+        if not hasattr(self, "_ignore_credentials"):
+            self._ignore_credentials: bool = False
 
         # If no credentials are provided, then determine the appropriate
         # defaults.
@@ -95,7 +97,7 @@ def __init__(
                                 **scopes_kwargs,
                                 quota_project_id=quota_project_id
                             )
-        elif credentials is None:
+        elif credentials is None and not self._ignore_credentials:
             credentials, _ = google.auth.default(**scopes_kwargs, quota_project_id=quota_project_id)
             # Don't apply audience if the credentials file passed from user.
             if hasattr(credentials, "with_gdch_audience"):
diff --git a/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc.py b/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc.py
index 916d2cc75c..87b5e7e0c0 100755
--- a/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc.py
+++ b/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc.py
@@ -143,7 +143,8 @@ def __init__(self, *,
 
         if isinstance(channel, grpc.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc_asyncio.py b/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc_asyncio.py
index b60d196552..e5c8f727eb 100755
--- a/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc_asyncio.py
+++ b/tests/integration/goldens/redis/google/cloud/redis_v1/services/cloud_redis/transports/grpc_asyncio.py
@@ -189,7 +189,8 @@ def __init__(self, *,
 
         if isinstance(channel, aio.Channel):
             # Ignore credentials if a channel was passed.
-            credentials = False
+            credentials = None
+            self._ignore_credentials = True
             # If a channel was explicitly provided, set it.
             self._grpc_channel = channel
             self._ssl_channel_credentials = None
diff --git a/tests/integration/goldens/redis/noxfile.py b/tests/integration/goldens/redis/noxfile.py
index eee3aad5cd..f16c08211d 100755
--- a/tests/integration/goldens/redis/noxfile.py
+++ b/tests/integration/goldens/redis/noxfile.py
@@ -167,6 +167,8 @@ def mypy(session):
         'types-protobuf'
     )
     session.install('.')
+    # Remove once https://github.com/googleapis/python-api-core/pull/650 is merged
+    session.install("google-api-core>=2.19.1rc0")
     session.run(
         'mypy',
         '-p',