Sorry but I think that this is damage rather than a mint error. We typically call these "vice-jobs" because they can be made by squeezing two (or more) coins together in a machinist's vice and thus imprint part of the design of one coin on another.
"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