I don't think it was defective when it was struck but it is now. I agree with Bill, that it looks like it was on the floor while someone was welding and the sparks melted it.
Maybe something like this 1853-C gold dollar? @Insider told me this is due to a lamination, but lettering looks too sharp to me to be that. As for the OP coin, I see more damage there than mint error.
Very interesting. To me all that excess metal to the right of the D suggests a die crack. Perhaps a fault in the planchet causes some metal to break off and a crack to squeeze out some metal. Just my two cents.
That is not a Planchet defect. It's Post Mint damage to the copper plating exposing the inner zinc. It's NOT a mint error of any kind. It's not Planchette it is called a Planchet. Two totally different things. Leave it alone.
