The gouge looks like a strike through and not PMD , since there doesn't appear to be any raised, displaced metal around it (as far as I can see from the pic) and there is some remnant if the top of the T showing. As to the ridges on the denticles? IDK. Maybe the die was starting to fail (or collar?) at the edge and the shard ended up on the die to leave a strike through. The rim looks like it might be a little wider on the right side of the void, which may also indicate some die chipping or crumbling at the edge. Not certain, but it sounds plausible.
Answer: Lamination. At first glance, it looked like PMD. Then struck thru became obvious until I saw the "peeling away" metal causing a split in the denticals. At one time, this was a complete coin. Then the large chunk broke away. At the top of the oval hole, you can see the horizontal tear. The tip of the "T" is now missing also as the lamination had originally covered its surface.
