Plutonium

I dont believe this has to do with plutonium

someone on reddit had the same issue with cod causing this issue
the fix is quoted below
"Found a fix. It was to do with the Windows Game Bar (Windows Key + G) Although I had to change the keybind for game bar in Windows settings (I Changed it to ALT + M) Then I was able to disable it in game. Try changing the keybind and see if it works for you!"

This is also happening to me, i've tried multiple things and its tough to play with having to walk before every gunfight. Makes me no match for the controller players using aim assist while im on m&k