When are the HitBoxes actually gonna be Nerfed? Not Buffed

That is a mix of latency or smoothing animations/interpreting lag. You'll notice she swung where you just were. This is because on her end, you had not moved yet. The info that you send to the killer is delayed because it physically has to travel between you and the killer in the real world, so you appear slightly behind where you actually are on their screen. Then when the killer hits you, it has to send that info back to you to register a hit on your end, which could make it seem more desynced.

The other half is the stuff the game does to make it look smoother. When you're playing an online game, where the other players are isn't a 1:1 representation of where they actually are. You are not receiving thousands of updates from every other player, you receive a set amount every second. Now if you just took that info and moved the players to their new positions, everyone would be jumping around and look incredibly choppy. To cover this, games will try to simulate movements. If you were here and you need to be there, it'll make you walk from here to there on everyone else's screen.

The important thing is that to get a hit, you were in front of them when they clicked. The game will register a hit and then go through the whole show and dance. If it registers a valid hit, it will lock on to the survivor and do the hit sound and effects, the survivor takes damage. The small amount of latency is mostly what makes it seem like they missed. If you time how long it takes to go from in front of the killer to the side of the killer, you'll notice it's about the same as your latency. If you look at this clip in particular, you'll notice that as she starts swinging you're still in front of her.

TL;DR: The important thing is that it's not giving them a hit they didn't actually get, it's just movie magic and latency that makes it look a little odd.