Comment 8 for bug 1890141

I am also affected by this really weird bug.
It happens on all applications that are using a fullscreen mode, no matter if in the browser or as a standalone application.
The videos i attached shows the problem when i use youtube.
It first starts normal for about 1 sec, then resizes, makes the second screen black and continues playing in just 1 fourth of the screen.
This is not very usable and extremly annoying.

I use a 4k monitor with 125 % as primary and a FHD monitor as secondary with 100% scaling.