It is quite possible that the coin is someone's poor attempt to create a "Bottle Cap Coin Error" which happens when a coin is struck outside of the Collar but to create the Bottle Cap effect, the coin must be struck perfectly centered. See the link below but it only shows one side of the coin which is concaved.
I have found dimes with similar wear pattern in large cloths dryers. Coins get stuck inside the machine and can wear for a long time until someone figures out how to get them out.