Lux's Lucen singularity (E) bug [GAME PLAY]

All of a sudden i couldn't cast my E anymore... In the spell description it say the spell costs 0 mana to cast and the icon was gray the rest of the match... When i pressed E or clicked the E icon i get the message "You cannot cast this right now!"

Q: How did this happened? A: I have no idea... The last E i casted was towards enemy graves who was shielded by his bottom lane inner turret... My E did not touch the ground -Wich means E flew and dissapeared instead of landing on the ground and stand there a few seconds- and my E went gray for the rest of the match...

As i say i did disconnect and reconnect and my E was still uncastable. I did died -on purpose ofc cause i can't die by mistake- and my E was still uncastable.

Additional information (might be helpfull). Graves's support was Zilean. Graves had poolparty skin, Zilean had default skin. I was Quinn's support. Quinn had phoenix skin, i had default lux's skin.

Hopefully this helps fix the bug.