After a WiFi session this morning the hosts chest with many items inside (iPad 2 iOS 6) disappeared after playing with the client (iPhone 4S iOS 6). I believe the client accessed the chest during gameplay and 'Copied and saved' when leaving. The items were not in the clients saved world.
Footnote: the clients saved world did not copy completely, some parts of the structures created by the host originally were generated as the world was when it was originally generated.
One issue per ticket please. These issues have already been reported.