I have a similar thing, but mine is on the same part but back towards where the storage box begins. I always have a soft terry cloth towel over all of it so that my forearm doesn't rub on it, so I know I didn't do it. It seems to be a clear coat of some kind.

Several members have reported the same problems.

I have tried to "rub it out" using a soft cloth and paint swirl remover, but it seems to be a defect in the material/finish. I think many people have some kind of defect, but like me, didn't notice it right away and the wonder how they did it.