If nobody is assigned to the groups you can delete them AFTER making sure there are no forum permissions associated to the groups.
And you can remove the dupe graemlins as well, I would imagine.
As to why they are being duplicated I'll leave to Rick to answer, I am not able to. <img src="https://www.ubbcentral.com/boards/images/graemlins/frown.gif" alt="" />