I have just found this whilst looking at other similar coins with variable edge lines…
See how the coin on the right (normal) has a 1mm flat, wide edge, but the coin on the left has a ‘scalloped’ slope with a narrow edge. It also seems to have variable numbers of reeding blocks around the edge, with 12, 13 or even 14 lines in each block, in stead of the usual 11. The distance of the date from the edge is also much wider.
