Is it the mark at 6 o’clock on the reverse? I would have thought it is a remnant of the removal of the sprue from the cast flan.
This might be the most logical explanation. However, the cuts seem to extend farther into the coin than I would expect from sprue removal.
The cut on the
reverse of this coin at 6h is the same as seen on the
obverse at about 8:30h. Also on the
obverse is a closed cut at about 3h (not seen on the
reverse as it doesn't go all the way through the coin). These marks are about opposite each other, as
flan sprues might be.