[Gameplay/Client]mouse acting crazy

I don't know if this is a bug with league or what but considering as soon as I end tasked League, it started working again. Basically at the "defeat" screen(lost a game, winning could probably produce the same effects), my mouse started acting erratic. It would not move from a certain position of the screen even after alt+tabbing. it just kept stuttering right back to the center quickly any time I moved it. This was EXTREMELY frustrating and probably the most annoyed I've been in a long time, because I literally could not do ANYTHING until I hit CTRL+ALT+DEL, suddenly it started working again, closed the end task screen and it started back up again, it didn't stop until I actually ENDED League's task.

I don't particularly know how to recreate the bug, other than possibly lose/win a game. At this point my mouse wasn't showing up so I hit alt tab and that's when I noticed it acting this way.