Merge pull request RasaHQ#5366 from DomAmato/bugfix/fallback

Fix bug where Fallback Policy always falls back when fallback action is action listen

Author: chkoss

changelog/5356.bugfix.rst

@@ -0,0 +1,2 @@
+Fixed bug where ``FallbackPolicy`` would always fall back if the fallback action is
+``action_listen``.

rasa/core/policies/fallback.py

@@ -144,7 +144,15 @@ def predict_action_probabilities(
 
         nlu_data = tracker.latest_message.parse_data
 
-        if tracker.latest_action_name == self.fallback_action_name:
+        if (
+            tracker.latest_action_name == self.fallback_action_name
+            and tracker.latest_action_name != ACTION_LISTEN_NAME
+        ):
+            logger.debug(
+                "Predicted 'action_listen' after fallback action '{}'".format(
+                    self.fallback_action_name
+                )
+            )
             result = self._default_predictions(domain)
             idx = domain.index_for_action(ACTION_LISTEN_NAME)
             result[idx] = 1.0