[GAMEPLAY BUG] Uncontrollable champion

everytime i play a game of LoL my champion just randomly freezes on the spot. And i am not lagging because my MS stays below 50 and frames per second above 50. the champion i use is uncontrolable like when you auto attack a champion and they move in the turret you can't do anything but watch your champion kill themself in the turrets. and when i try to flee from the enemey champions they just stand there taking all the hits. and you can kinda move when you try you just slide a few cm to the point you clicked on. I don't know how i got this bug like i said it just randomly happens to me in the middle of a game. and i get this bu like 15 times per 20 minutes.