Lux's Lucent Singularty disabled after use for entire game. "you cannot cast that right now"

I was playing an ARAM, fired Lux's E (lucent singularity) and the skill never actually went off. Instead, her E skill was just disabled for the rest of the match. When I tried to use it I just got the error: 'you cannot cast that right now' as if my champion were stunned. Putting another point into E did not fix it. Restarting the client did not fix it. I was able to use the spell a few times before this bug happened. I was firing the spell into the bushes when it stopped working.

I feel like this is a pretty game-breaking bug. I have no idea if it's specific to Lux, but I have never encountered it before with any other champion. I tried making a custom game by myself and repeating my actions to see if I could reproduce the bug, and was unable to.

It made for a very frustrating match when I finally got my favorite champion- a somewhat rare occurrence, as I play only ARAM and own almost every champion.

Anyways, hope it's figured out and fixed soon. Also, I'm wondering if there is any way to fix it in case it happens again in the mean time.