diff --git a/lib/carto/tree/definition.js b/lib/carto/tree/definition.js
index cbc65f05b..780e59612 100644
--- a/lib/carto/tree/definition.js
+++ b/lib/carto/tree/definition.js
@@ -232,7 +232,9 @@ tree.Definition.prototype.collectSymbolizers = function(zooms, i) {
 // resorting to the zoom range with the hole and stop processing further rules.
 tree.Definition.prototype.toObject = function(env, existing) {
     var filter = this.filters.toString();
-    if (!(filter in existing)) existing[filter] = tree.Zoom.all;
+    if (!(filter in existing)) {
+        existing[filter] = tree.Zoom.all;
+    }
 
     var available = tree.Zoom.all,
         objects = [],
@@ -241,7 +243,9 @@ tree.Definition.prototype.toObject = function(env, existing) {
 
     for (var i = 0; i < this.rules.length && available; i++) {
         zooms.rule = this.rules[i].zoom;
-        if (!(existing[filter] & zooms.rule)) continue;
+        if (!(existing[filter] & zooms.rule)) {
+            continue;
+        }
 
         do {
             zooms.current = zooms.rule & available;
diff --git a/lib/carto/tree/filterset.js b/lib/carto/tree/filterset.js
index a72ebc307..6c5957671 100644
--- a/lib/carto/tree/filterset.js
+++ b/lib/carto/tree/filterset.js
@@ -239,7 +239,7 @@ tree.Filterset.prototype.add = function(filter) {
 
     if (op === '=') {
         for (var i in this.filters) {
-            if (this.filters[i].key == key) delete this.filters[i];
+            if (this.filters[i].key == key && this.filters[i].op != '=~') delete this.filters[i];
         }
         this.filters[key + '='] = filter;
     } else if (op === '!=') {
diff --git a/test/rendering-mss/issue_343a.mss b/test/rendering-mss/issue_343a.mss
new file mode 100644
index 000000000..2d483391f
--- /dev/null
+++ b/test/rendering-mss/issue_343a.mss
@@ -0,0 +1,14 @@
+[zoom >= 12] {
+  [tourism = "attraction"] {
+    marker-type: ellipse;
+    marker-fill: red;
+    marker-width: 20;
+  }
+}
+[zoom >= 11] {
+  [tourism =~ "anythingelse"] {
+    marker-type: ellipse;
+    marker-fill: blue;
+    marker-width: 6;
+  }
+}
diff --git a/test/rendering-mss/issue_343a.xml b/test/rendering-mss/issue_343a.xml
new file mode 100644
index 000000000..46de23c40
--- /dev/null
+++ b/test/rendering-mss/issue_343a.xml
@@ -0,0 +1,23 @@
+<Style name="style" filter-mode="first">
+  <Rule>
+    <MaxScaleDenominator>200000</MaxScaleDenominator>
+    <Filter>([tourism] = 'attraction') and ([tourism].match('anythingelse'))</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#ff0000" width="20" />
+  </Rule>
+  <Rule>
+    <MaxScaleDenominator>400000</MaxScaleDenominator>
+    <MinScaleDenominator>200000</MinScaleDenominator>
+    <Filter>([tourism] = 'attraction') and ([tourism].match('anythingelse'))</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#0000ff" width="6" />
+  </Rule>
+  <Rule>
+    <MaxScaleDenominator>200000</MaxScaleDenominator>
+    <Filter>([tourism] = 'attraction')</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#ff0000" width="20" />
+  </Rule>
+  <Rule>
+    <MaxScaleDenominator>400000</MaxScaleDenominator>
+    <Filter>([tourism].match('anythingelse'))</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#0000ff" width="6" />
+  </Rule>
+</Style>
diff --git a/test/rendering-mss/issue_343b.mss b/test/rendering-mss/issue_343b.mss
new file mode 100644
index 000000000..40eb26c9b
--- /dev/null
+++ b/test/rendering-mss/issue_343b.mss
@@ -0,0 +1,14 @@
+[zoom >= 11] {
+  [tourism =~ "anythingelse"] {
+    marker-type: ellipse;
+    marker-fill: blue;
+    marker-width: 6;
+  }
+}
+[zoom >= 12] {
+  [tourism = "attraction"] {
+    marker-type: ellipse;
+    marker-fill: red;
+    marker-width: 20;
+  }
+}
diff --git a/test/rendering-mss/issue_343b.xml b/test/rendering-mss/issue_343b.xml
new file mode 100644
index 000000000..313b77b6b
--- /dev/null
+++ b/test/rendering-mss/issue_343b.xml
@@ -0,0 +1,23 @@
+<Style name="style" filter-mode="first">
+  <Rule>
+    <MaxScaleDenominator>200000</MaxScaleDenominator>
+    <Filter>([tourism] = 'attraction') and ([tourism].match('anythingelse'))</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#ff0000" width="20" />
+  </Rule>
+  <Rule>
+    <MaxScaleDenominator>400000</MaxScaleDenominator>
+    <MinScaleDenominator>200000</MinScaleDenominator>
+    <Filter>([tourism] = 'attraction') and ([tourism].match('anythingelse'))</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#0000ff" width="6" />
+  </Rule>
+  <Rule>
+    <MaxScaleDenominator>200000</MaxScaleDenominator>
+    <Filter>([tourism] = 'attraction')</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#ff0000" width="20" />
+  </Rule>
+  <Rule>
+    <MaxScaleDenominator>400000</MaxScaleDenominator>
+    <Filter>([tourism].match('anythingelse'))</Filter>
+    <MarkersSymbolizer marker-type="ellipse" fill="#0000ff" width="6" />
+  </Rule>
+</Style>
\ No newline at end of file