diff --git a/pyroengine/engine.py b/pyroengine/engine.py
index f3eedc4a..2ac62b27 100644
--- a/pyroengine/engine.py
+++ b/pyroengine/engine.py
@@ -291,10 +291,10 @@ def predict(self, frame: Image.Image, cam_id: Optional[str] = None) -> float:
             output_predictions = preds
             conf = 0
 
-        ts = datetime.now(timezone.utc).isoformat()
+        ts = datetime.now(timezone.utc)
         # Alert
         if conf > self.conf_thresh and len(self.api_client) > 0 and isinstance(cam_id, str):
-            self._stage_alert(frame, cam_id, ts, output_predictions.tolist())
+            self._stage_alert(frame, cam_id, ts.isoformat(), output_predictions.tolist())
 
         if self.save_captured_frames:
             self._local_backup(frame, cam_id, is_alert=False)