"I don't care what you say. Keep using that die until it falls apart. It's too expensive to keep replacing them and we need to make money, not spend it." Someone can be heard saying. LOL
I do find it interesting that dimes are more commonly found/posted with this degree of late stage Die Deterioration.
I am a member of a coin group on facebook. If this coin was posted there the replies would all be "Definite error." or "Get it graded." So refreshing to be part of a knowledgeable group. Have a great week!!!
I think that it might be a combination of a late die state with a lot of die fatigue and perhaps some time dipped in acid. This does not look like a Mint State piece to me. It's had something done to it after it was struck.