[BUG] Rengar's Empower W getting locked out.

Played a few games today, 2 of which i was locked out of using my empowered W. I pressed it so many times and it wouldn't go off. I also had this happen very early in the season around when he was first reworked, but no1 responded. This is 100% a bug and i would really appreciate some acknowledgement for it. [slayer-jinx-unamused]