User Logon Name is missing

Hi

Azure VMs

Domain Functional Level: WS2012 R2
Forest Functional Level: WS2012 R2
ADUC Server OS: WS 2012 R2.

We created new user accounts. However noticed that the "User Logon Name" value is missing for all these new users.

Is the "User Logon Name" mandatory or is it ok not to have it?

NB The User Logon name (pre-Windows 2000) is there with Domain\Logonname.

Thank you