diff --git a/imperative/python/megengine/traced_module/pytree.py b/imperative/python/megengine/traced_module/pytree.py
index 5a59fc1f..6cfcffde 100644
--- a/imperative/python/megengine/traced_module/pytree.py
+++ b/imperative/python/megengine/traced_module/pytree.py
@@ -189,7 +189,7 @@ def _leaf_type(node):
 
 
 def _is_const_leaf(node):
-    if isinstance(node, (RawTensor, NodeMixin, Module)):
+    if isinstance(node, (RawTensor, Node, NodeMixin, Module)):
         return False
     return True