[Gameplay] Sion's Q and R stopped working?

Midway through an ARAM game, my Q and ult would not activate on my key pushes. I was able to type 'q' and 'r' in chat and I was also able to use Q and R with his passive resurrection ability thing. I toggled my smart cast on and off and after that, it worked again. I'm not sure what I did to make is Q and R bug out.