[Gameplay] Anivia Q not actually being cast and then remaining active as if it was.

Periodically I will experience a bug while playing where you will cast her Q but nothing will happen, yet the ability will remain active as if the ability was cast but never reactivated or canceled. This greatly effects the ability to play Anivia effectively because of how reliant she is of how well her abilities interact with one another. I notice this bug most often while in team fights or in instances with high levels of action in the game, but i am not sure if that is actually what causes the bug to occur, as i have also noticed it while roaming though the jungle. I have not yet been able to recreate this bug as i have not found a particular set of circumstances that will make it occur.