Ekko's Q sometimes does not register.

(the video freezes for a second at the beginning, but its not broken)

Just finished a game, and near the end, I was chasing the enemy Jax to his fountain and would've killed him, and ended the game, but my Q, as Ekko, did no damage, didn't slow, and did not stack my passive despite hitting him.

Ekko's Q isn't supposed to expand unless it A. hits a champion or B. goes 700 units. You can see in the video that my Q has already expanded right next to where I threw it from, which means it 'registers' that its hit a champion, but has not applied any of its effects.

Dunno what else this could be besides a bug.