Started Minecraft on this iPad.

Opened a world that we'd been playing in in 1.4.3 for some time.

Joined from two other iPads.

Less than ten seconds after the other iPads had joined, Minecraft crashed on this iPad.

See attached crash log; I can't symbolicate it of course but I can see that the crash is a NULL dereference on the thread labelled MC_SERVER.

Here's the nasty part: when we relaunched Minecraft on the three iPads and rejoined, the players on two other iPads had completely lost their inventory, including what they were carrying.

Obviously, losing inventory is a seriously discouraging side effect for players.