Gameplay Globals not dealing damage

This is in reference specifcally to ult's such as ezreal's and ashe's "global" ultimates.

In 2 games recently, I've noticed the global skillshots hitting opponents but not dealing damage.

In the case of ezreal, he was using the pulsefire skin (probably not relevant), but there were two incidents where he would fire off his ult, the opposing nidalee would get hit, and no damage would be dealt. Both teams evidenced some manner of shock at this, so it wasn't just an individual client

In the case of ashe, it was a singular ult in a Co-op vs AI game, where the ashe bot fired her arrow (from what seemed an impossible angle considering her next known position), and the arrow passed through my character (jinx, firecracker skin) with 0 damage dealt, and no stun.

These have only happened inconsistently, so I can't provide any method of duplication, I just wanted to get the incidents out there, in the event that this is part of a larger trend