What does the date area look like?
If it looks like this but in the opposite direction, it is Die Deterioration.
If it is on the opposite direction, then it is machine damage after the strike.
It doesn't appear to be hub doubling because it is not enlarged like a doubled die.
Here is what hub doubling might look like on a doubled die:

If it looks like this but in the opposite direction, it is Die Deterioration.
If it is on the opposite direction, then it is machine damage after the strike.
It doesn't appear to be hub doubling because it is not enlarged like a doubled die.
Here is what hub doubling might look like on a doubled die:

























