So whenever my friend or other players change their skin their body parts decide to m=move to wrong locations or duplicate like in the image
sometimes players join like it too, I have seen it happen twice with arms sticking to the head, back items free floating where the arms should be, i have no clue what causes this 
(because Jira would not let me upload the image heres the link to the one screenshot i have of this error, https://imgur.com/teOJ1WD  )