What you are seeing is die deterioration doubling (DDD). This was the first year trying to strike new designs on the reverse and die were used well beyond their life expectancy. Their are many out their that are much worse. Welcome to CT Slate.
Welcome to CT @slate. Good eye to catch this and as already mentioned by @Pickin and Grinin, it was struck from a die that was at its end of life. Check out some sites about this. http://doubleddie.com Also, dies are cleaned and polished while in use, so you can get die abrasion anomalies.