I am going to take a stab at this. I am learning also. Planchets are not polished, dies are. You have an over polished die coin. Not an error. The polish lines all run together, hence, it came from the die. I will wait for the pros to reply.
Discovering the truth does not have all the answers.
so, is this die polishing plus a die chip? not a great picture, but the missing chunk is severe on its edges (like 90 degree edges severe). ... I guess a die chip would a raised blob... what would cause the missing chunk? from what I've seen chunks of polish (grease maybe?) usually result in blurry areas on the coin.
This die polishing was not just to remove clash marks, but also feeder finger scratches. This type of damage affects the dies so deep, that the busts deeper devices are affected. that is what you are seeing on this coin. This deep die polishing.