This coin was struck through a very thin, previously-struck fragment of metal. A thin piece of metal, such as a delaminated flake derived from a planchet, landed beneath the planchet that preceded the planchet represented by this coin. The flake was struck against this planchet where you find the motto E PLURIBUS UNUM and the flake molded itself to the corresponding recesses of the reverse die. The overlying planchet was then ejected and the struck flake moved to a different part of the striking chamber. A fresh planchet (this coin) came to rest on top of the struck flake, and the two were struck together. The result is a set of correctly-facing, incuse letters. The other possibility is that this cent was struck through a large, multi-element dropped filling. But the sharply defined borders and the lack of any other grease-struck areas makes this less likely
Error coin writer and researcher.