GAMEPLAY BUG

There is a Fizz bug with his Playful Trickster. Was in a game with brand, reksai, thresh, kalista and enemy j4, lux, warwick, zyra, and jinx. While fighting Jinx and Lux there became a point where my playful trickster was unusable and it was grayed out so I couldn't cast it. I tried to relog and restart client but nothing worked. For the rest of the game I couldn't use Playful Trickster so we lost. Please address this, it has happened more than once before.