A good question. I’ve noticed it myself, at least in the pictures. It must be on the coin but I do not remember seeing it in hand. Carbon spot, maybe? If so, I’d much rather see it on the rim or edge than in the fields or on the portrait. I really don’t know. I’ll have to take a closer look.
it's not so pronounced in the video as it is in the picture, but it's still there. maybe a flat spot not reflecting light the same as the rest and appears darker. But i saw that and feared contaminant or corrosion LOL .. the edges of that area sure are straight top and bottom though.
I do not recall any distractions when I had it in hand raw prior to sending it off to PCGS. They straight-graded it, and I will mention that the result mildly exceeded my expectations.