Ekko Q invisible bug

I was playing a game against an Ekko, he was using the sandstorm skin. Whenever he Q, I can only see the animation that he throws it out, but I can't it. This happens for every single Q since the beginning of game. Until at 17 mins I solo killed him, then it went back to normal. However that's not his first death in the game. I have no clue what triggered this bug. Is there anybody experienced the same? Cause this bug really influences gameplay.