[GAMEPLAY] Lux - Casting E can result in the spell being disabled for the rest of the game

Champion: Lux Items: Mejais (8 stacks), Athenes

I cast E and it made the sound effects, then the visuals disappeared as it reached the target location. My E then costed 0 mana and couldn't be cast for the rest of the game. This happened at around the 12 minute mark. As I cast my E i spammed the E button to detonate as quickly as possible.

20 minutes into the game: http://i.imgur.com/uIFgCrX.jpg http://i.imgur.com/qN3sw16.jpg 36 minutes into the game: http://i.imgur.com/gWFmZTA.jpg

Video: http://gfycat.com/RepulsiveDevotedAlpineroadguidetigerbeetle I'm assuming that when you throw out an E it switches to a 'different spell' to detonate it, on detonation the spell then switches back. The E just disappears in this bug so i assume that as it never detonates that the spell never switches back. Thought that could help.