Talk about a bad batch of medal......but also remember that the 64 nickels were very high mintage. That said quality assurance and die wear wasn't the best .
"Always hold a coin by the edge, never by the faces." -The first rule of collecting Anyway, even though that is a 64, I have no idea how it slipped through the workers at the Mint.
I bet it left the Mint in much better cosmetic condition. Chances are the lamination would still have been visible, but probably much tighter to the coin and the major piece off the obverse left post-Mint. It's had a hard life, and impacts along the way could have encouraged the lamination to split.
