I transferred a all white locked map from one world to another.
What I expected to happen was...:
The all white map to stay the same allowing me to use it.
What actually happened was...:
The map went almost fully transparent with the gray and white squares.
Steps to Reproduce:
1. In one world, create a new map.
2. Lock the map.
3. Save the map in your toolbar.
4. Take the map out in a different world.