Appears to be a lamination issue, in this case, a detached lamination. I’m not an expert on these, but 90% sure. Other members will chime in who know. I say 90% because there is an outside chance it could be a strike-through but the coin needs to be assessed in-hand, I think, to tell the difference. …imo…Spark
You are correct sir, a detached lamination. That makes it a genuine, bona fide mint error. Nice find.
I think it is a coin some one used a cutting device on it ( such as a chisel edge or lawnmower contact) some time ago. IMO Jim