Cone-shaped spells occasionally pass through people?

Over the past few days, I've seen this happen a few times. I've seen a Cho'Gath's roar pass right through somebody without damaging or silencing them, I've seen a Riven ult pass through someone without damaging them, and I'm pretty sure I saw it one other time but I don't remember who it was.

A few of my friends have noticed this too