fix: skip reasoning preceded by text

Author: Algorithm5838

backend/open_webui/utils/middleware.py

@@ -3821,6 +3821,10 @@ def set_last_text(out, text):
                             before_tag = item_text[: match.start()]
                             after_tag = item_text[match.end() :]
 
+                            # Tag in prose text, skip it.
+                            if before_tag.strip():
+                                continue
+
                             # Keep only text before the tag in the message
                             set_last_text(output, before_tag)
 
@@ -4381,6 +4385,14 @@ async def flush_pending_delta_data(threshold: int = 0):
                                     )
                                     reasoning_details_chunk = delta.get('reasoning_details')
 
+                                    # Native counterpart of `before_tag.strip()`: skip reasoning that
+                                    # arrives once the answer has begun.
+                                    if reasoning_content and output and output[-1].get('type') == 'message' and ''.join(
+                                        p.get('text', '') for p in output[-1].get('content', [])
+                                    ).strip():
+                                        reasoning_content = ''
+                                        reasoning_details_chunk = None
+
                                     # Only create a reasoning item for visible reasoning text.
                                     # Details-only deltas (e.g. Gemini encrypted blobs) are
                                     # buffered to avoid splitting the assistant message mid-stream.