On Release Build, if resolution is changed higher to desktop resolution, Mouse focus and game gets buggy / breaks

Hello,

We have recently released our game on steam. When players play the game, and their desktop resolution is 1920x1080. And when they attempt to do anything higher (4k for example) their mouse cursor gets buggy, You lose mouse focus, both the game cursor and engine cursor show up, of the game and when you click the game, it minimizes to the desktop. When you maximize the game you are restricted in a 1920x1080 box and unable to progress in the game with the mouse. We do check to make sure your monitor is compatible with the resolution in the settings so that if your’e monitor can’t handle 4k it won’t allow it. When you’re desktop monitor resolution is 4k however, it runs 4k just fine.

I am also using Windows 10, which I suspect may also be an issue.

Is there any type of fix for this?

Any help? I’m using Fullscreen btw.

Could someone help with this? It’s a Steam released game right now and our players are having issues.