Armours are very buggy in these betas: In this picture my girlfriend (who joined my minecraft world) looked like she was not wearing any armour, but she actually was. (We were sitting next to each other in real life, so we're sure that this is a bug, we even made some tests)
The opposite thing also happened: When she was not wearing any armour, she visually looked like she was wearing one.

Furthermore, sometimes she was not able to remove the armour that she was wearing (no curses on the armour)