diff --git a/imperative/python/megengine/traced_module/traced_module.py b/imperative/python/megengine/traced_module/traced_module.py
index c3328e1b90ba4ed65b8bc68b6476ebb5700a40d8..7e1a57f7a626c0679d6ebba9975a66b55751b362 100644
--- a/imperative/python/megengine/traced_module/traced_module.py
+++ b/imperative/python/megengine/traced_module/traced_module.py
@@ -2078,9 +2078,7 @@ class TracedModule(Module):
 
                 for node, repl_node in repl_dict.items():
                     assert node in graph._inputs or node in graph._outputs
-                    for i in node.users:
-                        if i not in repl_node.users:
-                            repl_node.users.append(i)
+                    repl_node.users.extend(node.users)
 
                 rename_blacklist = list(chain(call.inputs, call.outputs))
 
diff --git a/imperative/python/test/unit/traced_module/test_modification.py b/imperative/python/test/unit/traced_module/test_modification.py
index 820987e3b3a278b5abe4c51707d99b883fb2c5ca..9ac53730674e99e3f16e318c56b7151c16f7b8fd 100644
--- a/imperative/python/test/unit/traced_module/test_modification.py
+++ b/imperative/python/test/unit/traced_module/test_modification.py
@@ -6,6 +6,7 @@
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT ARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 import pickle
+from collections import defaultdict
 from itertools import chain
 
 import numpy as np
@@ -52,6 +53,25 @@ class MyModule(M.Module):
         return x
 
 
+class MyBlock1(M.Module):
+    def forward(self, a):
+        y = F.concat([a, a])
+        return a, y
+
+
+class MyModule1(M.Module):
+    def __init__(self):
+        super().__init__()
+        self.block0 = MyBlock1()
+        self.block1 = MyBlock1()
+
+    def forward(self, a):
+        a, y1 = self.block0(a)
+        a = a + 1
+        a, y2 = self.block1(a)
+        return a, y1 + y2
+
+
 class NewModule(M.Module):
     def __init__(self, traced_module):
         super(NewModule, self).__init__()
@@ -64,6 +84,17 @@ class NewModule(M.Module):
         return x
 
 
+def _check_expr_users(traced_module):
+    node_user = defaultdict(list)
+    for expr in traced_module.graph._exprs:
+        for node in expr.inputs:
+            node_user[node].append(expr)
+    for node in traced_module.graph.nodes():
+        node.users.sort(key=lambda m: m._id)
+        node_user[node].sort(key=lambda m: m._id)
+        assert node.users == node_user[node]
+
+
 def _init_cls(cls):
     module = cls()
     x = F.ones((1, 3, 3, 3))
@@ -201,6 +232,10 @@ def test_flatten():
     assert len(traced_module.graph._exprs) == 12
     np.testing.assert_equal(expect.numpy(), traced_module(x).numpy())
 
+    traced_module, x, expect = _init_cls(MyModule1)
+    traced_module = traced_module.flatten()
+    _check_expr_users(traced_module)
+
 
 def test_id_and_name():
     def _check_id(traced_module):