Upon entering the portal to the outer islands in the end the player becomes invisible.

I expected to be teleported 1000 blocks over the void and to be able to continue as normal.

What actually happened was that I was teleported as usual but instead of carrying on as normal I was invisible to other players and I was unable to use any items e.g. The Elytra.

To trigger the bug to as far as I have tested you must enter the portal to the outer islands on a multiplayer vanilla server.
Once through there's a chance that the player will vanish.
However, once you relog the bug will be fixed.

The first two images show one player launching fireworks directly in front of the other player with the other player's POV. The last screenshot shows the player trying to use the Elytra but instead of opening and gliding it does nothing. Instead the fireworks which propel the Elytra launch with no effect.
I have also included a screenshot with the version.