Only newly created users get a temporary profile, no UPD created

Hello! Since a few days newly created users get a temporary profile when logging in to our RDS 2012 R2 farm.

We have a farm with 9 RD session host, users have User Profile Disks and everything has worked fine for over a year. Now only newly created users get the temp profile pop up when logging on to the farm, and no UPD is created. When I check the registry ( HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList ) a *.bak item is created. When we delete it it's recreated whem te users logs on again.

Existing users who we have created a few weeks earlier have no problems at all.

I'm a little stuck here, any help is really appreciated!