[GAMEPLAY] Jarvan IV Not Doing AutoAttack Animation

I was playing in a custom SR game as Jarvan IV, with the Darkforge Jarvan skin (in case that matters). I had a Vel'koz on my team, Lux and Zyra on the other team (all real people), and my first item was relic shield+potions. When I went to use the relic shield execute, Jarvan didn't do his attack animation, but the minion was executed and money was distributed correctly. For the rest of the game, only about half of Jarvan's attack animations would happen- the other half it was just Jarvan doing his standing animation and the enemy's health decreasing. It was unclear whether I was actually attacking when I tried to attack minions or champions, and there didn't seem to be a pattern in it. (Attacking a turret seemed to be fine)

I asked my friends who I was in the game with, and the lack of animation was apparent to everyone.

Hope this is enough to go off of.