To me it looks like the edge of the incuse area on the die was widened a bit with a little polished out area. Why do I think that? Note nothing else on the die is affected on the digits are like that. If this were hub doubling they other devices would look the same. I ruled out MD also as nothing else appears to be affected. The thing that goes against my theory is that, why would that area be polished? Not sure why area would need polishing. Maybe that edge was damaged? Look at the NE area of that device? Seems like something was alter there?