When converting an old save (38MB) to the new update the xbox displays a minecraft sync process that always gets stuck at 12% then it closes showing me a window saying "there is a problem converting your world save" then i seng my world save and minecraft tries to sync again (stopping at 12%) then it appears a message (within minecraft) that i have to connect to the internet (i was always connected to xbox live)

This is not a random problem that i encounter... it always happens to the same world save in the same way (always gets to 12% sync progress)