When opening the social interactions menu, if you are in spectator mode, your skin will not update. It will be shown as a default skin.
- Join a world in first person view
- Go into spectator mode using the command /gamemode spectator
- Exit and rejoin the world
- Open the world to LAN
- Open the social interactions screen
- Notice how the skin appears to be a default skin
- Change the tab to 'Hidden' and back to 'All'
- Notice how the skin updates