I play Fizz a lot in Dom, and also experience this bug.
It's been happening for a long time, and as far as I can tell, it seems to happen when the timing of your E-button presses are on the edge of the timer for deciding go/fail on performing Trickster, or just flopping to the ground.
I suspect what's happening is that part of the game thinks he did Trickster, and plays the animation, but when it goes to calculate the damage, goes back and says "Whoops! You actually missed it by 0.1s. No damage for you!".