When you want to change the user UPN, in certain conditions, this UPN change will not be synchronized to AAD (Office365/Intune/other).. why?
When you have federated domains for Office 365, or rather AAD in general and you want to switch your users from one domain to another, you will notice that that object will replicate anymore to AAD (and thus Office 365). I noticed this a long time ago, and it seems Microsoft now also posted this as a known KB a few weeks ago..
In my previous post, I talked about the possibility of using Kerberos Constraint Delegation to avoid having passwords in AAD. However, sometime you want to have a few passwords in AAD-Domain Services to ensure that administrators can still login to the VM’s interactively (RDP) or users are able to use certain services that are not published with Kerberos or aren’t web services.
In this post we will look at editing the configuration of AAD-Connect to synchronize the passwords* of users that have an attribute in AD present so that some users (like administrators) will be able to login to VM’s joined to AAD-DS using their on-premises passwords.
* see note below