Realm player settings not saving

Im trying to update the priveleges of a user to admin on my realm, but the status is not saved.
He is admin on the xbox app.
But when i/he enter the realm, he is just a normal member with no priveleges.
When i try to change his priveleges from the game menu (both before and after entering the realm), the changes are not saved.
I press the (+++) icon before his name and he get a yellow crown, as im expecting, but as soon as i press back, its gone.

How do i give him priveleges so that he can change game settings at the same level as me?

The mojang support says to report this as a bug.