Placing 2 different maps in the anvil converts one to a duplicate of the other

Tablet Nvidia Shield

Steps to reproduce:

1.Have one active map enhanced with compass and other map, which is created in different position and it is not enhanced with a compass.
2. Open the anvil dialog.
3. Place both map on the first select anvil slot. I have placed it there, because I don't know, which map is on the anvil. It would be good to know it.
4. Cancel via X button the anvil dialog -> the maps are putted on the ground.
5. Pick up the maps -> both maps are in the same slot (see the attached picture) and both maps are equal to the map, which was not enhanced with a compass. So you loose the data on the first map that now shows the same data as the second map and also the map doesn't show the position sign anymore.