Mundo's Q is invisible in ARAM
Just played a game in ARAM where the enemy team had Mundo. None in my team could see him throwing his Q (the animation of Mundo throwing the cleaver and of the target being hit by it could be seen, but the cleaver in mid-air was invisible); the enemy team, instead, reported that they could see every part of the animation.
Edit: this bug happens only with the classic skin.