I’ve tried repeatedly to transfer a world the size of exactly 293.2 MB, but the resulting transfers only give me worlds the size of just above 100 MB, though it appears to range slightly between the different transferred worlds. Strangely, the entire western portion of the world generates entirely new terrain while the eastern half is old terrain (both pictures 1 & 2), builds and all. The dividing line cuts through the origin exactly with one exception right at the origin where a section of chunks on the east side generated new terrain unlike the rest of the eastern half of the world (seen in picture 2, the corner of the desert is exactly the origin of the world). If I were to guess the problem, I would say the cause might be a limitation on how much information the transfer tool can convert before completing the process, though that’s only coming from successfully transferring smaller worlds and no real knowledge on the topic.

Edit: I should also mention that when loading these maps in for the first time after transfer, they are prone to freezing if I fly around to load chunks in, so I usually am idle for about a minute to allow the world to process. I just mapped the coordinates of the strange ungenerated section of chunks on the eastern half of the world. They begin at 0,0 and end at 256,256 (8 chunks by 8 chunks) if that’s of any help. Of all the reports I’ve seen of such issues, pretty much every single one talks about larger worlds crashing before conversion even finishes with vague reports of similar instances to the one I’m dealing with. If anyone can find a similar issue with more responses, I’ll be sure to check it out.