Lux's E Unusable [GAMEPLAY]

During one of my games as Lux support, I was using Lux's E and it worked, but about 5 minutes in the game the ability icon grayed over as if it was on cooldown, however there was no timer, and when I tried to use it, it said the ability wasn't ready yet. And it remained that way through the rest of the game. My keyboards "E" worked just fine, and every game with Lux after that worked. It was just that one game. So I don't know if the problem is consistent with other users. But, it happened, and it should be checked out, thank you!