diff --git a/libs/langgraph/langgraph/pregel/loop.py b/libs/langgraph/langgraph/pregel/loop.py
index 9496847ca..943cfdfc2 100644
--- a/libs/langgraph/langgraph/pregel/loop.py
+++ b/libs/langgraph/langgraph/pregel/loop.py
@@ -228,7 +228,9 @@ class PregelLoop(LoopProtocol):
         if self.stream is not None and CONFIG_KEY_STREAM in config[CONF]:
             self.stream = DuplexStream(self.stream, config[CONF][CONFIG_KEY_STREAM])
         scratchpad: Optional[PregelScratchpad] = config[CONF].get(CONFIG_KEY_SCRATCHPAD)
-        if not self.config[CONF].get(CONFIG_KEY_DELEGATE) and scratchpad is not None:
+        if not self.config[CONF].get(CONFIG_KEY_DELEGATE) and isinstance(
+            scratchpad, PregelScratchpad
+        ):
             if scratchpad.subgraph_counter:
                 self.config = patch_configurable(
                     self.config,