Parent account cannot join realm after child account joins.

I have a bug (or what I identify as a bug) with Switch account and Realms and the Microsoft Account. This is a technical login issue.

On my switch I have 3 users. One parent and 2 restricted accounts. All of them linked to unique Microsoft account with unique gamer tag. When I connect to realm with each one of them and I use the list command I can see that correct gamer tag associated to my Switch user.

When I use the split screen of my Nintendo Switch to connect to realm for the 2 restricted account + a connection from a PC with the parent account I cannot connect with parent account. I get e message telling me the account is already on the Realm. 

More strange. When I connect the User 1 then I add the User 2 I get this error message but when I connect User 2 then User 1 I can play with all 3 users.