This was working a few days ago, then the bug kicked in.

Unable to change player permissions on my realm.

Our basic permissions are set to visitor, but now when I try to change the permission to member, it doesn't change and acts buggy instead.

It is impossible to change any of my realm members from 'Visitor' to 'Member,' on Windows 10 AND Xbox One!

It looks like the other reports for this bug are over a year old.  Not sure if you claimed fixing it or not, but it is an active bug...