Changes to Material Instance Parent don't appear to propagate to child instances if the child instance's editor window is open

It looks like this occurs when the grandchild instance window is open. If you close and reopen the Grandchild's window the parameter appears as expected. I've attached a project with the setup steps completed for the above repro.

1. Create a new material named M_Parent
2. In that material create a new StaticSwitchParameter named ignore-Switch
3. Create two scalars, one set to 0 and the other set to 1
4. Connect the 1 value to the True input of ignore-Switch
5. Connect the 0 value to the False input of ignore-Switch
6. Connect the output of ignore-Switch to Emissive
7. Save and Apply the material
8. Create child of M_Parent called MI_Child
9. Create a child of MI_Child named MI_Grandchild
10. Open the editor for both MI_Child and MI_Grandchild and array the windows side by side.
11. In MI_Child, toggle the override for the ignore-Switch parameter and set it to True.
12. Observe that even though the material becomes emissive, the ignore-Switch parameter in the parameter panel shows False and Reset to Default even though it isn't overriden.