Self Cast hot key only works half the time

I use Alt + Ability binding and self cast is only working half the time. It's not my keys either because my alt key works just fine when not in League. (I just tested it) It's gotten me killed multiple times trying to heal/shield myself because it just doesn't go off. I used to never have a problem with it until this patch. It's happening about 1 out of every 5 times when trying to self cast.