fix

chain_service/database/models/progress_chain.py

@@ -68,6 +68,9 @@ class ProgressChain(BaseMongoModel):
     ):
 
         for action in filter(lambda c: c.action_type == "comment", chain.actions):
+            if not action.text:
+                continue
+
             for key, value in variables.items():
                 action.text = action.text.replace(f"{{{{{key}}}}}", value)