looks like Two coins were fused together at one time with JB weld or something similar and then was pried apart with something sharp. That's just a guess but I feel certain it did not leave the mint looking this way. PSD or PMD IMHO
Are you sure that it is metal? We see this sort of thing with the raised material being dried clear glue all the time. You could give it a soak in acetone and see if the raised section comes away from the coin.
"If you climb a good tree, you get a push." -----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed." -----King Adz