Meow thinks there might be something there. A bit of soaking to get the small chunks out the way might help.
I see what you're seeing too. I have no idea what it is - just find it funny with discoveries & speculations. It could be a "second D" but I wouldn't count on it becoming your next fortune! Thanks for the share anyway!
I saw it instantly, so it stands out, but whether it is pareidolia or a "dropped letter" is hard to tell. With it in hand, try to measure the supposed D to see if it is the same size as the mint mark. If it is, I'd send it in to be authenticated. Good luck and let us know the outcome.
Meow thinks the mint mark maker was dropped on the die, leaving a very light randomly placed mint mark.
It's a scratch and a couple of gouges that raised some metal. It's nothing but damage. I've highlighted multiple other similar scratches. It's not even raised above the surface (compare the light on the date and the real D), except maybe a little where the metal was gouged. What's supposed to be the bottom left of the D isn't even joined together, and what's supposed to be the top and right doesn't have the correct curve, and it's not even the right size. It's useful to flip these things upside-down and then see what you think you see. This is damage and an optical illusion. My evaluation.