fix duplicate assistant text events

engine/product_protocol.py

@@ -18,7 +18,6 @@ from pipecat.frames.frames import (
     OutputAudioRawFrame,
     OutputTransportMessageFrame,
     OutputTransportMessageUrgentFrame,
-    TextFrame,
     TranscriptionFrame,
     UserImageRawFrame,
 )
@@ -64,9 +63,9 @@ class ProductWebsocketSerializer(FrameSerializer):
                 timestamp=frame.timestamp,
             )
 
-        if isinstance(frame, TextFrame):
-            return self._event("response.text.delta", text=frame.text)
-
+        # ProductTextStreamProcessor owns response.text.* events. TTS also
+        # emits TextFrame subclasses internally, and serializing those here
+        # would make the UI render duplicate assistant bubbles.
         if isinstance(frame, (OutputTransportMessageFrame, OutputTransportMessageUrgentFrame)):
             if self.should_ignore_frame(frame):
                 return None