I was planning to host a Minecraft server with the buffet world type using the jungle biome, but then I found a bug with the buffet world type that only happens on multiplayer servers. The buffet world types work as intended on singleplayer, but on multiplayer servers, the buffet world type always generates ocean biomes, even though the level.dat is the correct biome. I have the biome set to the biome that I wanted it set to in the generator-settings line in server.properties. Also, the chunk generator works as intended, however. I triggered a debug crash to help make debugging the issue a bit easier.

Generator Settings:
generator-settings={"biome_source"\:{"type"\:"minecraft\:fixed", "options"\:{"biomes"\:["minecraft\:mutated_jungle"]}}, "chunk_generator"\:{"type"\:"floating_islands"}}