Kind of reminds me of a ragged end clip. But it's not a clip because you still have the whole Obverse side. Maybe a defective Planchet on the Reverse side only. Like a lamination before strike. When the Reverse was struck the Obverse side near the date sank, or sunk in due to lack of metal on the other side. It still has the upset rim on the Obverse. It's hard to damage the Reverse without affecting the Obverse. Maybe a possibility IMHO
Defiantly not PMD, Could be a bad planchet. Details opposite of the anomaly on the obverse are very weak and there are some very weak details of "AMERICA" in the recess of the reverse.
