diff --git a/libs/langgraph/langgraph/advanced_graph/state.py b/libs/langgraph/langgraph/advanced_graph/state.py
index da00c047e..2d6038c28 100644
--- a/libs/langgraph/langgraph/advanced_graph/state.py
+++ b/libs/langgraph/langgraph/advanced_graph/state.py
@@ -269,9 +269,6 @@ class _GraphEngineRun:
             update = result
             sends = _normalize_result_to_sends(result, default_input=node_input)
 
-        if update is None and isinstance(state, dict):
-            # Preserve in-place state mutations for prototype nodes like wait_node.
-            update = state
         if isinstance(update, dict):
             update = _reduce_update_to_changed_fields(before_state_snapshot, update)
 
diff --git a/libs/langgraph/tests/advanced-graph/test_sub_agents.py b/libs/langgraph/tests/advanced-graph/test_sub_agents.py
index bb8f343b8..2613edec3 100644
--- a/libs/langgraph/tests/advanced-graph/test_sub_agents.py
+++ b/libs/langgraph/tests/advanced-graph/test_sub_agents.py
@@ -109,11 +109,11 @@ def build_main_agent(planner: MockLLM, sub_agent: Any) -> Any:
             elif channel == "user_input_channel":
                 state["output"].append(f"user_input: {payload}")
             # State changed -> ask planner what to do next.
-            return Command(goto=Send("llm_node", None))
+            return Command(update=state, goto=Send("llm_node", None))
         else:
             state["output"].append("timer: no updates yet")
             # No meaningful state change -> keep waiting without calling planner.
-            return Command(goto=Send("wait_node", None))
+            return Command(update=state, goto=Send("wait_node", None))
 
     async def tool_node(ctx: Context, tool_input: str) -> None:
         await asyncio.sleep(0.1)