Does look like the person touched the spine a bit too far back on the tang and may have had an oh craps moment! Then again what glen said about the razor not ground right to begin with and the tang not tapered to allow for clearance on the stones, and the "regrinder" got a bit over zealous...a mystery for the ages I guess.
Glen, I took a few strokes with the 8k and where you have it circled at the spine is the contact point, on both side. I switched out to the 4k and proceeded to focus my pressure on the heel. After about 30 minutes, the heel began to come in line with the rest of the blade edge as I also reduced the shoulder thickness The reflection on the heel makes the transition seem more severe than it really is. Under the loupe, it is a gradual, even transition. I suppose the next step is to see how it hones…...
What a pain this one was. There's enough of the shoulder remaining at the heel to create a wobble where the blade won't sit flush on the hone. On the Naniwa 1k: So I tried the 45° long stroke—heel forward, straight down the hone—after some circles to bevel set. The biggest issue I was having was getting an even bevel. The center of the blade was fine, but the toe and heel lagged behind. Eventually I got a decent bevel across the blade—but it took me forever to get the right 'feel.' Finished through the series of stones (4k/8k/12k); pasted strop with ChromOx; and then linen/leather. popping hairs across the blade so that's a good sign. Tomorrow's shave will tell me more…..