A couple of years ago, there was a full body painted PC, same gray colors as ours, for sale on the internet showing the Diamond Shield had turned a dark blotchy brown resembling a roasted marsh mellow. I suppose you'd want to examine occasionally for such an indication if there was a reaction to worry about. On that PC, I think the Diamond Shield damaged the paint behind, so if you see a serious problem developing, I would consider removing the Diamond Shield before paint damage occurs.
Hopefully something else caused the damage on that PC's Diamond Shield so what I caution over doesn't apply here.