[Bug] Camera freaks out then locks on champ

Randomly while playing on summoners rift, the camera spazzes out and then locks on to my champion. I can no longer move the camera by mousing near the edge of the screen. The camera just follows my champion and it's very disorienting!

Pressing the toggle "lock camera to champ" hot key (Y) doesn't unlock the camera. The only way I can unlock the camera after it wildly darts about and then locks on my champ is by dragging the mouse around the minimap and forcing it off the champ that way. It stubbornly snaps back to my champ a few times before spazzing out again and returning to it's regular functionality

Please reply with any information you have about this bug, i'm genuinely interested on why this happens