Katarina's skills becoming unusable
I was super fed as Katarina. Just finished getting a few kills near their inhibitor. My reset worked properly but my Q and Recall were unusable until I died. I tried restarting, swapping the keybinds, and alt-tabbing -- still nothing. Apparently getting yet another reset works as well, but that is relatively difficult without your Q. No idea how to reproduce. Play a game as Katarina where you're getting a bunch of resets, it'll happen.
Imagine the shoutcasters if this happened in a tournament... Lol.