Brad Bumgarner

I'm experiencing something similar to this ticket combined with this: https://bugs.mojang.com/browse/MCPE-26064 in version 1.4.2.  I only recently started playing Minecraft in the last 2 months so I think all of my experience with the game is in the Better Together edition.

Pablo, I think I'm experiencing the same thing you are with some additional issues.  My "synced" games lose their titles.  My creative maps change/ show survival as the type, but when you attempt to play them they act like a half survival half creative mess.  The syncs corrupt causing the maps not to render fully and huge holes appear in the map.  Time spent building in a map on one console is not fully there in the other map, appearing in bits and pieces... and often appearing as a large hole all the way through the map.  These holes drop all the way through to below bedrock - even in a survival map. For instance, I was paddling South in my boat in an ocean and looking East. I paddled into a hole in the ocean and fell through to below bedrock and died. Since it is a survival map and I fell to the bottom of a hole in the ocean, there was no way to retrieve any lost items. 

 See the images I added as xbox_one_s.jpg and xbox_one_1.jpg - images from two different consoles in my home on the same network.