The clue that it is a grease error? Note the devices are wider looking. That is because the deepest areas of that die, had grease that prevented the strike up of those devices. Note how they are wider looking? The devices are tapered. Wider at the base and smaller at the top of the devices.

Why do they do that? If they didn't the coin would be stuck into the die on each strike and would have to be removed on each strike. Thus the tapering of the devices.
CoopHome:
What are die devices tapered? How does a Grease Fill on a die alter the strike? to allow the coins to not stick onto the dies. grease prevents the strike from happening on a die void. contained grease or oil can stop even a strike from happening. Hydraulic Jacks work on this principle. Contained chamber with added push, lifts even heavy stuff.