Here is the 1944-D D/S Die #1 And here is the 1944-D D/S Die #2 Both of these images are from Variety Vista, which can be found here-http://www.varietyvista.com/ This is the best site I've found for 20th century die varieties, especially doubled dies. I've been a member there since 1990.
With the new photos, I see what you are seeing, but the S is too small to be a mint mark, or a dropped letter, not that it could be, so I guess we both have pareidolia. LOL
When I look at your photos with the circles and arrows I can see it, but not in the others. Wrong size anyway, possibly an optical illusion?
So here is what I learned and gathered about everybody's opinion. Most agree that it is not the famous D over S because in that error the D dominates and in my photos the S dominates. It's not two mint marks because the S is too small to be a second mint mark. Some think it may be considered a variety OMM rather than an error. Perhaps it could be something but just not sure what! Does that sound about right?
Looking at your photos I would agree with those who said neither is an OMM. Just as Paddyman98 indicated. IMO, Jim