Vi's Q doesn't work

A few times now, as I go in game, my Q suddenly stops working. The system is registering, hell I can even type Q in the chat, and register it as the Q command, but it doesn't work.

I can't even click cast the ability, it's as if it doesn't exist.

Apparently this has been going on since last season. When's this going to be fixed? Vi is quite literally unplayable without her Q.