Thank you all for your responses. I knew that I'd seen something like this before on the forum - thanks @Chase. It may well be "crimper" damage as noted. If it is, I can only guess that this coin was put into some sort of aftermarket set at one time. The photos make it appear that the coin is well-circulated, but it has a beautiful gold tone and hard luster that I wish I could capture for you. I'd love to know the journey this humble Jefferson has taken.