Yep, still broken. Checked on PS5 again this evening, patch downloaded yesterday.
Been a month with no Minecraft since we can't play on the family realm together.
I thought we had tested on an offline world last week, but this guest account issue seems to only be affecting us on Realms.
We can login to our offline worlds splitscreen and to our proper accounts.
Only when trying to join our Realm in splitscreen does the second player get dumped intoa guest account.
This was happening prior to the chase the skies update as well, at least a month or two.
PS5
As above, first person to log in has their gamertag, and the second person is on a guest account with no inventory, and at world spawn.
Possibly related/another symptom of the bug's source: Sometimes it shows 2 guest accounts have joined the game. Attempting to interact with the mystery third player/second guest via the menu (eg to view profile, set permissions, or kick them) in these cases causes the game to freeze up and have to be force closed.