Note both sides of the coin is showing the same thing. A pair of wore cutters damaged your coin. On a
Cud, that is a breakaway of the outside edge of a die:

On a
Cud, one side is usually affected, the opposite side show weakness:

Note how the metal is taller than the rim of the coin? Also note on the opposite side, there is a weakness there. So with the void on the die, the opposite side of the coin does not receive pressure to make the devices full. That is how you can tell you have a
Cud. Sometimes there is a crack on both dies, but the only example I have show the
Cuds in different areas of the opposite dies:

Hope this helps.