F11 zooms in and distorts picture

Hi guys,

I’ve been having this weird glitch for some time now, also on 4.15. Every time I want to go into immersive mode and press F11, the picture zooms in by what it feels like 400% and gets tilted and distorted. I tried taking a snapshot of the problem, but the actual screenshot looks just fine.
Extra info you might want to know: I’m running one 4k monitor on GTX1070.
Can someone suggest what could be the problem?