Can add Server Groups but can not revoke them

EDIT: It seems to work now. Maybe the server needed some time to update? Or the user tested hat to relog? idk but it kinda works now

So my idea was to create server groups which can be added and removed by any users.
The problem is that only the admin can remove them again even though i correctly set the needed / powers.

The group that I created (lunatic).

The group that the most users currently have (normal).

for some reason if i change the group remove power from normal group to 75 it works again.
can anyone help me out?