Same thing happened to me in SMP. I had two maps, both of them in item frames and expanded to the largest size. One was of the area the map was placed in, while the other was of the area to the north. I logged out of the server, and when I came back, I took both maps out of the frames. The First map continued to show the green arrow, despite no longer being in an item frame, and I discovered that, by travelling past the edge of the map that the terrain was a layer above the player icon, thus obscuring everywhere except the very edge. I have not tested to see if the player icon shows up in unexplored areas, so it is possible that the player icon would show up there as well, but only for a split second before being covered up again. The other map has a weird glitch as well, where instead of the green arrow showing up (which wouldn't happen since it was placed in a frame outside its range), the white icon (for the player's spawn point?) shows up with no icon for the player. I went into unexplored terrain as well as to the edges, but the player icon never showed up, despite the map updating like normal. I observed this behavior all in a vanilla SMP world.
Aaron Marymee
Same thing happened to me in SMP. I had two maps, both of them in item frames and expanded to the largest size. One was of the area the map was placed in, while the other was of the area to the north. I logged out of the server, and when I came back, I took both maps out of the frames. The First map continued to show the green arrow, despite no longer being in an item frame, and I discovered that, by travelling past the edge of the map that the terrain was a layer above the player icon, thus obscuring everywhere except the very edge. I have not tested to see if the player icon shows up in unexplored areas, so it is possible that the player icon would show up there as well, but only for a split second before being covered up again. The other map has a weird glitch as well, where instead of the green arrow showing up (which wouldn't happen since it was placed in a frame outside its range), the white icon (for the player's spawn point?) shows up with no icon for the player. I went into unexplored terrain as well as to the edges, but the player icon never showed up, despite the map updating like normal. I observed this behavior all in a vanilla SMP world.