We have set up a GPO that has a security filtering using security groups. The GPO is linked to the OU, the server is a member of the security group (IN THE AD - more in a moment).
We have not rebooted the server since it was added to a new group in AD, so the server does not know that it is a member of a new group. We can see this if we perform GPRESULT on the server. The new group is not shown.
But the GPO is applied, it works. I dont get why though.