diff --git a/backend/open_webui/routers/retrieval.py b/backend/open_webui/routers/retrieval.py
index 979cd2c70..250d27eb3 100644
--- a/backend/open_webui/routers/retrieval.py
+++ b/backend/open_webui/routers/retrieval.py
@@ -124,7 +124,7 @@ def get_ef(
 
 
 def get_rf(
-    reranking_model: str,
+    reranking_model: Optional[str] = None,
     auto_update: bool = False,
 ):
     rf = None
@@ -762,6 +762,9 @@ async def update_query_settings(
         form_data.hybrid if form_data.hybrid else False
     )
 
+    if not request.app.state.config.ENABLE_RAG_HYBRID_SEARCH:
+        request.app.state.rf = None
+
     return {
         "status": True,
         "template": request.app.state.config.RAG_TEMPLATE,