diff --git a/api/streaming.py b/api/streaming.py
index e496b2a2..8e4cef70 100644
--- a/api/streaming.py
+++ b/api/streaming.py
@@ -3312,6 +3312,7 @@ def _preserve_pre_compression_snapshot(s, old_sid: str) -> None:
             snapshot.pending_user_message = None
             snapshot.pending_attachments = []
             snapshot.pending_started_at = None
+            snapshot.pending_user_source = None
             snapshot.save(touch_updated_at=False, skip_index=False)
             logger.info(
                 "Marked pre-compression session %s as sidebar-hidden snapshot",