Hi
A friend of mine had the exact same issue. It would appear that there were some very subtle differences on the version for the GS1200 - this resulted in his tank surround being marked. He contacted GIVI and sent in photos. I am sure that he was told to get a newer version of the fitting, and they replaced the damaged part.
He knew that something was wrong because he bought the bike from me and I had a GIVI tank ring fitted previously without issue. When I next see him I will ask him to refresh me of the exact details.