While playing LAN worlds with my brother and friend, we noticed that what ever armor we put on and/or any items we hold does not update (visually) for the other players until: you log out and log in, they log out and log in, you die, or they die.
Happens in: Any gamemode
Happens on normal servers too: Haven't tested
(we have not tried the latest snapshot so I'm assuming that it is still present since it wasn't in the bug fix list)
Duplicate of MC-14220, please use the search function to see if your bug has already been submitted. Currently over 55% of tickets are being closed as duplicate.