Nextcloud maps LDAP users as admin

Hi all, I’m configuring LDAP on nextcloud 12.
Everethin went fine.
I created a group named ‘cloudusers’ on the domain controller and associated a user named ‘testad’.
Nextcloud shows ‘testad’ user and the group ‘no group’.
If click on ‘no group’, ti will show the windows ‘authenitcation required’.
I close it without inserting a password and the group shown is now ‘admin’.
Once the page is refreshed, ‘no group’ is correctly shown again.

Is it possible that your browser auto-filled the form? Try to log on different browser/desktop please.