In the Metals world we would call this a "Cold Flow". I don't see how it could have happened at the Mint either. Might have been sharp when it occurred and has "smoothed" out from wear. Idk.
...the scratches on the cheek and neck are evidence of circulation, the ear is evidence of damage, the fine lines in the field by the chin is evidence of improper cleaning. ...jmho...Spark
hey bgator welcome to CT. your coin sure spikes the curiosity meter doesn't it. it may have been dropped