Screenlock bug [Client]

I encountered a weird bug while playing Caitlyn the other day. My screen got locked onto my character and would not unlock. I tried hitting 'y' the default unlock button, and it did not work. I clicked the button above the mini map and still nothing. I spammed the space bar, and again, nothing. The only thing I can remember doing for the bug was using the mini map to look up top. And then after I release my mouse from the mini map my screen snapped back to Caitlyn and my screen was locked. It has only happened once, but it is game breaking glitch so I would like it to not happen again. :)