In-game bug with Sion

I was playing a match with Sion , everything was going fine but half game i couln't cast my Q nor my R (W, E and Summoner Spells worked fine). It wasn't my keabord because i could type those letters in chat, and I also tried to change key shortcuts fot the spells but didn't work. It was a problem with the champion? with the server? Hope you can check it out so it won't happen in the future. Stay awesome Riot!