This bug is connected to the "Quit and save map" function in multiplayer games. It seems that only chunks loaded in devices's memory get saved.

What I expected to happen was...:
When I was leaving a multiplayer world with a "Quit and save map" feature, I expected that the whole map will be saved, including all the changes, buildings, mines etc. I expected, I could be able able to use this feature to copy my maps or to save other people's creations.

What actually happened was...:
I quit and saved the map. When I opened the map again, I have found that parts of the map reversed to their original state before the players made any changes to them - i.e.: buildings were saved incorrectly, most of the creations were broken. It seems that only the parts of the map, which were loaded into memory were saved. I have tested this many times on multiple devices (both iOS and Android)

Steps to Reproduce:
1. You need two devices (I tried iPhone 4S, iPad 2 and Nexus 7) - the bug affects all of them.
2. On the first device, open a survival map, to which a lot of changes has been made (lots of farms, buildings, mines etc.)
3. On the second device, connect to this first device's map as a second player.
4. On the second device, quit with the "Quit and save map" option
5. On the second device, start a game and select the map, you have saved
5. Walk through the map to see that some of your creations were not saved and that some parts of the map reversed themselves to the original seed.

See the two attached images for comparison of what should have been saved and what was saved.

What would I want it to do?

I would like the "Quit and save map" function to crawl the whole map, load it into memory, chunk by chunk and save it exactly as it was on my friend's device.