Patheon Ult Brooke’s can lock

Okay, I play LOL with Camlock on all of the time. I have my ult and am planning to jump into the teamfight. I use the mini map to move my cam and cast my ult. While this is happening I am also moving my cam around to see if there is anything I should be aware of. Then I land and we are slaughtering them. They try to escape. We follow. Except, I stop short of chase. Patheon is on the edge of my screen and now when I move my mouse to the side it moves my cam. I trying pressing y again to lock. Doesn’t work. I remap it. Still doesn’t work. It only works again after I die sometimes.