@ssf, to me this looks like a combination of circulation flattening plus the use of a slightly worn punch to add the mm to the die. Alternatively, the mm punch might not have been perfectly perpendicular to the die. Either way it seems pretty minor, but could be worth saving if you want an exemplar.
"If you climb a good tree, you get a push."
"The danger we all now face is distinguishing between what is authentic and what is performed."