AA seems to have a lot of one-stop (one flight no.) flights to/from ATL; for example to places in the Caribbean, which come and go. Right now AA 1700 shows as a direct flight to SJU (with a stop at MIA.) If you look in December, it's gone. I suspect ATL-(MIA?)-STX was one such at one time, and somehow got stuck on the map. Then when it went away the map didn't get revised.