XB1 Beta: Hang: Once, on first launch of beta - trying to sync old worlds resulted in extended hang [resubmitting to correct project]

Description
On the first launch of the Minecraft beta, accessed through the Xbox insider testing platform - trying to sync old worlds and then pressing B during the loading screen resulted in an infinite hang. Could not interact with game any longer. Had to go to dashboard and quit game. Could access dashboard etc - just not any in game content

Steps to Reproduce

1. Obtain Xbox account with previous Minecraft Xbox One world save games.

2. Sign up for Xbox Insider and acessss the Minecraft Beta

3. Join newcomer server and read all help/directions/information

4. Back out to main World menu

5. Click "Sync Old Worlds"

6. Notice extended loading time for first time sync

7. Press B to exit before sync complete and notice hang

8. Notice only option is to press the XBox button and exit game

Successful reproductions/attempts
Reproduced 1/5. Only occured on first attempt syncing world's

Actual Result
Game entered hang when B was pressed to stop sync, and user had to force exit game

Expected Results
Game does not enter hang if user presses B to exit before sync finishes / game functions as designed

Notes
XB1 Better Together : beta 1.2.0.20
I do not have any recording software or other tools at home
I was unable to get this to repeat even with multiple attempts - leads me to believe it had something to do with the first initial sync and trying to exit
Let me know if you would like any more information.
*Resubmitting since posted in wrong database*

Key Words - sync , old worlds , Xbox , hang , infinite , soft lock , Xbox one beta , Xbox one update preview