I was looking at an indent on a cion I received recently (the lot with the Vetranio issue) and thought it looked a bit like a counterstruck bust or a lamination. It was a few minuted before I realised it was a double strike - this bit being the nose and mouth and some of the legend being struck in the hair. The picture is oriented so the double struck portion is correctly aligned.
Interesting but not major and I already have a drastic overstrike so I may not keep it (need to save up, after all).

A quick analysis of the strike - the first strike was way off center, so I think it was intentionally restruck (and carefully, its fully centered on the flan).