I launched the Alpha for my game that uses universes/“games” and players report that they get turned into guests after being teleported to another instance of the game. This happens to about 2% of the people.
Here’s the game: Swordburst Online - Roblox
already reported could of at least looked down 2 post 
All related to the new login system, it’s also causing this bug. Roblox is known for having this issue, it isn’t the first time. When Universes first launched this issue was even more viral. I remember this, because Universes and the Egg Hunt came around the same time and everyone was complaining about joining as guests at the Egg Hunt.