Moving the file location of the Editor Startup map appears to break the reference to the startup map

Moving the file location of the Editor Startup map appears to break the reference to the startup map. The editor fails to find the map and so does not use it for the start up map.

Notes:

In the maps & modes section it still has the name of the map that was set even though it is not being used.

If Fix up redirectors is used, the startup map will be set to None

1. Open the Third person template
2. Create a new level (Make sure that it's not completely blank)
3. Save that new level
4. Set it as the Editor Start up map (Project Settings > Maps & Modes > Editor Startup map)
5. Move the map to another folder
6. Restart the editor
7. Notice that the editor did not use the Startup map that was set

Expected: The editor would use the Startup map that was set or would provide a warning
Result: The editor fails to find the map and so does not use it for the start up map.