diff --git a/src/bot/io_layer.py b/src/bot/io_layer.py
index 0c32324b..60a2f154 100644
--- a/src/bot/io_layer.py
+++ b/src/bot/io_layer.py
@@ -76,7 +76,8 @@ class BotIOLayer:
             return src, self.query_topic_map[src]
         if self.query_topic_chat_id:
             return self.query_topic_chat_id, self.query_topic_id
-        return src or None, self.query_topic_id
+        # No mapping/fixed topic configured: reply directly to source chat without topic.
+        return src or None, 0
 
     def send_query_message(
         self,