Yeah, that bubbling looks like the metal has been melted. A clearer pic is needed, but I would lay money thats post mint.
Torchin turns em purple then black and to make copper-nickel cladding "bubble" you'd have to raise the temperature close to melting which is 2,140 degrees F. The pure copper core melts at 1,983 degrees F. I have no idea what occured with the OP's coin.