HELP!! There is a bug with Sion

Sions ability to use his Ult and Q are gone, at a certain level. You can hear the sound that sounds right before the skill is activated but the skill doesn't activate. Riot if you see this please fix the problem for me. Sion is my main so I have nothing else. I believe it occurs after you max his Q but I can't be sure. If you could fix it that would be great! Thanks!