[GAMEPLAY] - Lux ability (E) suddenly became disabled not being able to use for entire game

Was playing Lux on ranked. Was using E ability and on one time trying to detonate the ability when suddenly it became disabled for entire game (grayed out). My guess is because the game thinks that E hasn't been detonated yet?

1. I'm using smart cast
2. When the bug occurred, the description says that the ability costs 0 (zero) mana
3. Nothing would help to fix it (i.e. restarting client. machine, self cast, etc).

Lost the game as was useless for entire game (this happened on min 3-4 into the game). Please do loss prevention. Thanks.