Created attachment 9250 [details]
View of Administrator account in ADUC.
In a newly provisioned Samba4 AD, the Administrator account has no UPN in ADUC.
It doesn't have one in a Windows ADDS domain either. As far as I know, this is because the initial Administrator account is copied from SAM to AD during dcpromo, SAM does not use UPNs, the attribute is optional in AD, and there is no reason to assign one.