Constructed blocks disappearing in Multiplayer survival mode

MCPE World is actually being served up on an IPad 2, also running 0.5.0. When the IPod Touch (4th gen) user builds large structures, not all of the construction appears on the IPAD screen, or another IPOD Touch also connected, though they do appear at that time on the IPod Touch of the person building the structure. When that person logs out and logs back into the game, those blocks are missing. This is new behavior to the November 0.5.0 release, not seen in the prior release. Only seems to occur in survival mode.

IPod Touch 4thgen and IPad 2's were all running IOS 6.0.1

The lost construction has been done with wood planks. Not sure if other material are disappearing this way