[GAMEPLAY] Sion spells doesn't work

Whenever I play Sion I have problems with his q and r spells. At the start of the game I don't have problems, I can cast the spells but during the game, q and r spells stop to work and I can't cast them! I tried to change them keybindings or cast the spells with my mouse but i can't click on them.. I also tried to reinstall the game but the problem persists... I hope you'll help me or fix it if it's a bug.