Ran across this on
ebay. It does not appear to have the correct position or markers for a D/S. Nor does it seem to match any D/D repunched mint mark on Variety Vista or Wexler. Nevertheless, it has a strange and compelling shape. Maybe it's
Machine Doubling or a thin die chip along the mint mark cavity? Puzzling.
https://www.ebay.com/itm/366642015866