I was leaning towards PMD on it, but see both possibilities. The line is just too straight with a height difference, but maybe it's just me.
How does that layer "PMD" off? I was wondering, at first, too, on how straight it is. I think it had to originate on the blank. It was there on the sheet from which the blank was cut. It upset into a planchet and was struck by the dies. Look at how evenly the line parallels the graining. Something was weakening along that direction. Or maybe the shock of the strike lifted it off. That's plausible, too, it seems to me.