Neat. Could be a Planchet Lamination issue. Can't be totally sure though. Is it like a copper flap? Can you stick a thin piece of paper under it? Like this Lamination.. From my collection
Certainly appears to be "something" on top of Lincoln's face. I'm thinking a strike through. A scrap piece of metal from other planchets became impressed on the coin, so debris in the press. Just my thoughts on it.