The key to ID is the ORIGINALITY of the surface inside the circular cut into the coin. If it is natural you have somethig. What, I don't know. I'm still PMD just because I have never seen this before on a coin. It is not a lathe mark.
I was wondering if it could be lathe marks. But if the circle is incuse rather than raised, I’d vote damaged. I’ve found lathe marks on cents and nickels. Both on their reverses and raised.