I remember there was a discussion about such a variety some time ago. The strap underneath the chin here is incuse into the surface of the coin. Upon magnification, it shows as two parallel lines, perhaps 1/4 mm apart.
Anyone know anything about it?
Thanks!

Here are close up pics, one normal and one with contrast. Notice the fork like shape where it touches the underside of the jaw.
Die clash? I'm not too familiar with how those type of errors look.
