diff --git a/tests/unit/gui/test_busy_overlay.py b/tests/unit/gui/test_busy_overlay.py
index b7043113..cf188c2d 100644
--- a/tests/unit/gui/test_busy_overlay.py
+++ b/tests/unit/gui/test_busy_overlay.py
@@ -62,7 +62,9 @@ def test_robot_cooling_is_the_only_blue_busy_state():
 
     def _style(activity: str):
         # Only .activity.value is read; cast keeps basedpyright off the stand-in.
-        tell = cast(TellStateModel, SimpleNamespace(activity=SimpleNamespace(value=activity)))
+        tell = cast(
+            TellStateModel, cast(object, SimpleNamespace(activity=SimpleNamespace(value=activity)))
+        )
         style = build_busy_overlay_style(is_busy=True, tell_state=tell)
         assert style is not None
         return style