[GAMEPLAY] Lux E doesn't detonate/unable to use ability

While playing Star Guardian Lux, midgame during a teamfight, I used her E and it wouldn't detonate. The visual disappeared off the map, but the skill was unusable for the rest of the game - the ability icon showed a grayed out E as if it wasnt leveled yet. Even though the visual disappeared off the map, it gave vision on everything walking through where the E used to be for the rest of the game through the fog of war.

This is the first time it happened while playing Lux ((sad life we lost that game bc I basically only had 3 skills left as Lux))