Universal Hitbox/Hurtbox Interaction Issue

On occasion, circumstances doesn't seem to matter (happened on summoners rift, happened on aram), an ability will just refuse to interact with the enemy's hurtbox. It's happened a couple of times in the past two days now, and I just saw it happen in the chinese Yuumi gameplay video. First time I was playing Pyke, ulted a Vlad who had just gotten out of his pool, he was directly in the middle of the cross and it did no damage (not just didn't execute, I know it's possible that he healed out of execute range, but it just didnt hit). Second time was a Blitz pull on ARAM going straight through someone and not hitting. It also happened int ARAM with a couple of other projectiles, but i don't remember which champions were involved. This isn't a case of hurtboxes just barely being out of the hitbox, I guarantee it just whiffs straight through. And just now I saw Yuumi's missle go straight through a Vayne but then interact properly and hit Soraka.

Before and after of the Pyke interaction: (https://i.imgur.com/qZdc4Mz.jpg) (https://i.imgur.com/tVoPYkS.jpg)