Coding of this souls-like mechanic never works when full screen [help needed]

As you can see in the video, when I kill an enemy I got some points, but this only happens when the editor window is not full-screen, and when it’s full-screen, it doesn’t work. I got some other errors only in full screen too, so weird. Help really appreciated.

If you are using widgets, then make sure the widget component is anchored. Anchoring the widget component keeps its location no matter the resolution size.