I think i found something there.
When i was in NetherPvP, i found some1 just have a founght each others.
and i tried to show the hitboxes while they're fighting (F3 +
and this is just happened
When i saw these screenshots, NORMAL hitboxes will just showed 1 Blue Line when we saw something. (Picture 3)
and the Error hitboxes showed tons of lines (more than 1 blue lines), like a bug. (Picture 1-2)
i'm not sure about this, i/we still waiting for staffs fix the bug later.
Umm done? Used all your brain?
A hitbox is a wire frame that surrounds an entity. Player is an entity so it has a wireframe on it and a blue line that shows what direction is "that" particular entity is facing.
Oh sorry for being rude, but I think you don't know that arrows are also considered as entities and so is that one more wireframe.
A character is pretty big and it can hold other entities on it like arrows. So, when an arrow is shot and it hits the ground, a wireframe/hit box can be seen around it. Whereas if an arrow hits a player it gets stuck on to the player and stays there for 1 min (arrows are deleted by default after 1 min has elapsed) and hence you see many hitboxes in pic 1 and pic 2.
Pic3: You weren't shot by a bow as you were spectating/not participating in the fight and hence only 1 hitbox is shown in the inventory gui.
This same effect can be seen when you have enabled the hitboxes ( f3 + a ) and you ride a minecart in 3rd person perspective. 2 hitboxes can be seen, one is of the player and other of the minecart.