When transferring worlds for the small ones they converted just fine. My world of 358.9mb had problems however. The game only transferred 176mb worth. I tried this many times and the same glitch happened.
Do to this all my world from the center to the western most part of my world had all the chunks being reset and overwritten. Lost all builds and terrain were this happened.
The eastern parts of the map were fine. along with some chunks in the north and all in the south east.