I solved it myself after a lunch boost in energy. 😉

Here is the command I used:
sudo dseditgroup –o edit –a “Domain Users” -t group –n /Local/Default staff

The answer should be something like this:
‘staff’ upgraded to new group format in order to support GUID membership.

And if you check it with:
dscl . read /Groups/staff

You should find something like this:
NestedGroups: AAAAAAAA-BBBB-CCCC-DDDD-EEEEEEEEEEEE

Hope this helps someone.