[Samba] Problem to change values with ldbedit if primary group is 512 (Domain Admins)

[holgi]

Dear samba community,
I wanted to delete roaming profiles for some users with ldbedit 
according to the wiki
https://wiki.samba.org/index.php/Roaming_Windows_User_Profiles#Using_ldbedit_on_a_Domain_Controller

It works well for every user being in 513 (Domain Users) as 
primaryGroup. Some of our users have 512 as primaryGID. For those I'm 
not able to change any value with ldbedit.
I always get the following error:

failed to add CN=(xyz01) NameX,CN=Users,DC=domain,DC=local - The primary 
group isn't settable on add operations!

Does one of you have any idea how to get around this issue?

Running Samba Version 4.15.13-Ubuntu

take care
Holgi