diff --git a/source/tests/pt_expt/test_plugin.py b/source/tests/pt_expt/test_plugin.py
index a59242e592..61e4ba071d 100644
--- a/source/tests/pt_expt/test_plugin.py
+++ b/source/tests/pt_expt/test_plugin.py
@@ -22,12 +22,42 @@ def fake_entry_points(*, group=None):
         return [_FakeEntryPoint(calls)]
 
     monkeypatch.setattr(importlib.metadata, "entry_points", fake_entry_points)
+
+    # Snapshot the deepmd.pt_expt module tree BEFORE re-importing. Just popping
+    # "deepmd.pt_expt" and leaving its submodules cached poisons sys.modules
+    # for the rest of the pytest process: a later import of a cached submodule
+    # (e.g. deepmd.pt_expt.infer.deep_eval) re-creates a BARE parent package
+    # whose submodule attributes (utils/infer/...) are never rebound, and
+    # mock.patch("deepmd.pt_expt.utils...") then fails with AttributeError on
+    # py3.10 (shard-order dependent CI failure).
+    saved = {
+        k: v
+        for k, v in sys.modules.items()
+        if k == "deepmd.pt_expt" or k.startswith("deepmd.pt_expt.")
+    }
+    deepmd_pkg = sys.modules.get("deepmd")
     sys.modules.pop("deepmd.pt_expt", None)
 
     try:
         importlib.import_module("deepmd.pt_expt")
     finally:
-        sys.modules.pop("deepmd.pt_expt", None)
+        # drop everything the fresh import created, then restore the snapshot
+        # (including the parent-package attribute binding).
+        for k in [
+            m
+            for m in list(sys.modules)
+            if m == "deepmd.pt_expt" or m.startswith("deepmd.pt_expt.")
+        ]:
+            sys.modules.pop(k, None)
+        sys.modules.update(saved)
+        if deepmd_pkg is not None:
+            if "deepmd.pt_expt" in saved:
+                deepmd_pkg.pt_expt = saved["deepmd.pt_expt"]
+            elif hasattr(deepmd_pkg, "pt_expt"):
+                # deepmd.pt_expt was not imported before this test; the fresh
+                # import bound it onto the parent package, so drop that stale
+                # attribute to leave the parent exactly as we found it.
+                delattr(deepmd_pkg, "pt_expt")
 
     assert groups == ["deepmd.pt_expt"]
     assert calls == ["load"]