Katarina bug [GAMEPLAY]

I was playing Katarina yesterday, and when I tried to flash ult someone as they flashed away, I encountered a bug. They had flashed at the same time as me, so my ult went off but not a single hit had hit a champion. After the ult had ended, I was unable to cast my Q, R, Recall or summoner spells. I attempted to fix it by disconnecting and reconnecting, but that didn't fix the issue. I tried dying, and that is what fixed the bug.