I've experienced this issue a couple times now where junk data is randomly getting saved to the biome object files.

I'm curious if the bo3's aren't being closed properly and its causing this issue.

Junk data? As in seemingly random bytes?

I'll have a look.

I see you tried to fix this in 330e8b5 , but that cannot possibly be the cause. The variable streamForUncompressed was part of a try-with-resources block, which closes the resource automatically. So the added .close() call is redundant.