Bug with Smart Pings as the Nexus is destroyed

I was in a game with some friends, right as we we won the game I tried to use the "enemy is missing" ping. The ping icon (with directions) disappeared as expected when the explosion animation started, but then when the victory screen popped up my mouse froze in the middle of the screen, where LoL has (0,0). I could move my mouse but it would immediately bounce back to the middle. The weird part was, after I alt tabbed to manually close the game client my cursor in the windows desktop did the same behavior of being stuck at (0,0), this time in the upper left hand corner. When I Ctrl Alt Deleted to open task manager I could control my mouse outside of the desktop but as soon as I went back to the desktop the behavior returned. When I closed the ingame LoL client with task manager my mouse function immediately returned to normal.

I'm on windows 8.1, patch 5.16 of LoL.

tl;dr: tried to ping as the nexus exploded, mouse froze both inside and outside of game