Attempting to replace an object that hasn't been fully loaded (UserWidget)

It’s in line 150

It was used to store the ptr to the currently focused widget. For example, when I’m hovering a Widget with the mouse, it tells the UISystem to set this Widget into focus.
I thought I’ll make it a UPROPERTY because some pointers are garbage collected after 2 minutes ingame. In this case the reference cant be lost because the ptr is provided from outside this class, but I did it just in case.