Sync Not Working

For the Minecraft Better Together version,

Using the 'Sync Old Worlds' option isn't working. After I sync a world, it generates with terrain overlapping most of my buildings, and majority of the buildings are completely absent! One thing I noticed is that before I sync the world, the size is 253MB, but after the world syncs, it is only 150MB. Sometimes, when I try to load this world, it often crashes my entire Xbox, so I have to restart or turn off the console! (I think they released a patch today that was supposed to fix this but it did not!)

Please and thank you!