1988 LMC Rim?

Nice pictures. looks like it could be a die chip/break.

OK, my ignorance could be showing here, but wouldn't a Cud start out with small die cracks leading from the rim into the field of the coin? When two small cracks from the rim meet a short way into the field, the resulting piece of the die would break off creating a Cud. I think (and I could very well be wrong) that this is just a die chip. Stress at this point could lead to the conditions creating a Cud, but I don;t think this is the beginning of a Cud. Chuck and Bill (and others in the know), where are you?

Die chipping. Think about the shape of the die. Stand the die on its base so the so the striking surface is at the top. The field is flat going out toward the edge. Then the field stops and it drops down a short distance and then continues out flat to the edge of the die. That drop and second flat area are what form the the inside wall and upper surface of the rim. If the die chips there at that corner where the field ends and the drop begins you will get a raised lump right there where the field meets the inside edge of the rim on the coin. And that is exactly what you have. Frankly I don't know why we don't see it more often.