Error when updating DNS Roles

I went to add some details to the DNS Roles of ther server.  I click edit server and go through to the DNS Roles, however I cant seem to remove any of the DNS settings, I click delete and they go, however each time i click update DNS Roles, they re-appear and seem to duplicate at the same time.  Ive now got about 10 copies of my dns settings?? Am i doing something wrong? Surely you can delete these settings?
 
Im on HC 8.00.0012
 
Thanks