I can confirm that if you place a map inside an item frame at one location and the remove it, and place at another location with the same map, the first green marker will remain until you exit out of the world save in single player.
I have also had achievements reset. As Levon stated, I also have not had achievement reset after updates. I would also like to note that I loaded a backup of my achievements into my folder and after 3 tries they were not accepted.
I can confirm that if you place a map inside an item frame at one location and the remove it, and place at another location with the same map, the first green marker will remain until you exit out of the world save in single player.