diff --git a/agent/component/loopitem.py b/agent/component/loopitem.py
index 71b91c810..b656ea789 100644
--- a/agent/component/loopitem.py
+++ b/agent/component/loopitem.py
@@ -113,6 +113,10 @@ class LoopItem(ComponentBase, ABC):
                 return len(var) == 0
             elif operator == "not empty":
                 return len(var) > 0
+        elif var is None:
+            if operator == "empty":
+                return True
+            return False
 
         raise Exception(f"Invalid operator: {operator}")
 
diff --git a/api/db/services/document_service.py b/api/db/services/document_service.py
index 81bd160e3..95cf4da76 100644
--- a/api/db/services/document_service.py
+++ b/api/db/services/document_service.py
@@ -701,6 +701,8 @@ class DocumentService(CommonService):
                     v = [v]
                 for vv in v:
                     if vv not in meta[k]:
+                        if isinstance(vv, list) or isinstance(vv, dict):
+                            continue
                         meta[k][vv] = []
                     meta[k][vv].append(doc_id)
         return meta
diff --git a/deepdoc/parser/pdf_parser.py b/deepdoc/parser/pdf_parser.py
index 539cd007d..b704d25ea 100644
--- a/deepdoc/parser/pdf_parser.py
+++ b/deepdoc/parser/pdf_parser.py
@@ -1447,6 +1447,7 @@ class VisionParser(RAGFlowPdfParser):
     def __init__(self, vision_model, *args, **kwargs):
         super().__init__(*args, **kwargs)
         self.vision_model = vision_model
+        self.outlines = []
 
     def __images__(self, fnm, zoomin=3, page_from=0, page_to=299, callback=None):
         try: