Happened to me. I know the reason bebind such problem (not sure if it works in every case). SO basically long time ago I was playing apex on my low end pc and to juice the most fps out of it I went to registry editor and made sure apex.exe is always running on HIGH cpu priority level. After that my game basically started to stutter when moving the mouse around, while fps actually decent and no such things were suppose to be happening, I tried many things, but changing the CPU priority back to NORMAL, fixed the issue, my mouse was moving normally again. Im not sure if this have something to do with cpu or windows/game running in high priority but I hope this helps you, try to check if you force the game run on high cpu priority and if it does, lower it to ''above normal'' or ''normal''. You can also find couple of tutorials how to do it. Good luck.