The 1984-D and the second coin are both definitely PMD (post-Mint damage). If the chunk missing from the 1984-D had been clipped or cut out during the blanking operation the edges of the missing section would have been plated with copper like the rest of the coin. Your photos are very out of focus but I am certain that piece was cut out of the coin after it was struck. The second coin is severely worn and corroded. What happended to the coin to cause this? I don't know. I wasn't there. But it did not leave the Mint in that condition. I can't tell for sure what is going on with the 1987 but it looks like either an air bubble below the copper plating or zinc rot. It could also be glue on the coin. Hard to say from the photos.
