See all the other 'hits' above the date, on the rim, etc? And, the flattened right side of the D mintmark ? Same - contract or hit marks from circulation
Yea, I thought for a sec. it might be a bubble, but look at both sides of the coin - lots of contact marks, including just the left of the 'disturbance', where the right side of the D is flattened. Damaged in that area, imo (and if it was a bubble, the coin is so damaged I don't think it matters)