First, let me say that I understand Pareidolia (the tendency for perception to impose a meaningful interpretation on a nebulous visual stimulus) but, if that is what this is, it's the darnedest one I have ever seen. Give me your thoughts, Please!
If you look at his thumbnails, the top right has a file name of shadow S, so I assume he thinks he is seeing a S mintmark in that damaged area next to the D
Without reading others posts, I put my pareidolia to work and saw a faint S, but know it is just a spot on the coin that leads one to seeing things.