diff --git a/gateway/run.py b/gateway/run.py
index 8447dd0f51..5682d00346 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -9396,8 +9396,10 @@ class GatewayRunner:
                                 pass
                         except Exception as e:
                             logger.debug("Stream consumer wait before queued message failed: %s", e)
+                    _previewed = bool(result.get("response_previewed"))
                     _already_streamed = bool(
-                        _sc and getattr(_sc, "final_response_sent", False)
+                        (_sc and getattr(_sc, "final_response_sent", False))
+                        or _previewed
                     )
                     first_response = result.get("final_response", "")
                     if first_response and not _already_streamed:
diff --git a/tests/gateway/test_duplicate_reply_suppression.py b/tests/gateway/test_duplicate_reply_suppression.py
index f454d75eb0..3c2c7b32c8 100644
--- a/tests/gateway/test_duplicate_reply_suppression.py
+++ b/tests/gateway/test_duplicate_reply_suppression.py
@@ -324,9 +324,24 @@ class TestQueuedMessageAlreadyStreamed:
     def test_queued_path_detects_confirmed_final_stream_delivery(self):
         """Confirmed final streamed delivery should skip the resend."""
         _sc = self._make_mock_sc(already_sent=True, final_response_sent=True)
+        response = {"response_previewed": False}
 
         _already_streamed = bool(
-            _sc and getattr(_sc, "final_response_sent", False)
+            (_sc and getattr(_sc, "final_response_sent", False))
+            or bool(response.get("response_previewed"))
+        )
+
+        assert _already_streamed is True
+
+    def test_queued_path_detects_previewed_response_delivery(self):
+        """A response already previewed via the adapter should not be resent
+        before processing the queued follow-up."""
+        _sc = self._make_mock_sc(already_sent=False, final_response_sent=False)
+        response = {"response_previewed": True}
+
+        _already_streamed = bool(
+            (_sc and getattr(_sc, "final_response_sent", False))
+            or bool(response.get("response_previewed"))
         )
 
         assert _already_streamed is True