When you freeze someone as Mei in many situations their Hitbox and Model will go out of sync, making it impossible to tell where their head is. This is most evident with large models, such as tanks, but it happens with everyone.
Model and Hitbox are desynced; Video proof
For this first video I set up a Workshop game where Reinhardt stays frozen for an extended amount of time. The text “No” shows up when the shot was not a headshot". “Headshot” shows up when it was.
In this example I am spawning a red effect where I am looking. If the sphere shows up on Reinhardt, that’s where his actual model is. If it’s on the wall behind him, the shot should have missed. As you can see his hitbox expands well beyond him.
From 0:40 you can see just how crazy far his head is from his actual hitbox. It’s no where even close.
Exhibit C, real game example.
You can see I clearly hit him in the face, but to no result. You can see how his model weirdly turns while he is frozen.
Exhibit D, it’s not exclusive to Mei.
In this clip we watch from the perspective of Ashe. You can see her clearly hit 3 headshots, all of which registered as body shots.
Exhibit E, It’s not just exclusive to Reinhardt.
In this case it’s happening to Roadhog. Once again you can see his model weirdly shift as he gets frozen. None of the shots register correctly.
But it goes beyond a messed up Hitbox
Hits register client side, but do no damage at all. Clearest example at 0:20. The hit effects show up, blood flows, but no damage is done and no hitmarker is shown. Also just look how stupidly wrong hit hitbox is. This is the same reinhardt in the same position as the second video. Hit head and back are so far apart, I can’t imagine what hit hitbox looks like at this point.
In this example I am trying to shoot through the gaps of his hitbox. Some of my projectiles don’t render at all. It gets fired, it hits the wall, but between that the projectile does not render at all.
Once again, I want to stress, even though Reinhardt is used in most of these examples, it happens to absolutely everyone. Big models are the most obvious but I’ve had it happen to Genji, Lucio, Mercy, Tracer, and just about everyone else.