we had a survival map for quite some time, when maps were able to be duplicated we decided to make maps for both of us (there are only two people on the server) it worked fine until item frames were added, then we wanted to make waypoints on our map using more duplicate maps and item frames. duplicating done with an empty map.

when we put the first two maps in the item frames it worked fine, but on the third extra map we noticed it didn't make a green arrow on our map. so taking it off and using the other version of the map in my hand made the green arrow appear. but then I "fell" through the map myself, so I quickly swapped back with the map on the frame, I broke the frame but the arrow stayed, however i was still not on the map. i later walked into an uncharted area to see myself for a second or two under the terrain being charted.

Steps to Reproduce:
1. duplicate a large map use the duplicate to make more copies (I think the issue lies here)
2. put the maps in various item frames around a world, we put ours in the villages we found.
3. you will notice on the 5th active map (there was me and my friend with maps on at the time, as well as two maps already working perfectly) will not show on the item frame, the actual map will be there, but not the green arrow. like I said through experimentation I noticed that the arrow still existed it was just under the terrain.

One line fix by Angs can be found in this comment