Not Natural Generation
I've tried it without Terralith and tried it without a couple other things I just can't think of now. I've tried changing from a release version to a new beta version of Biomes O Plenty. Oh! I tried disabling things that were specifically involved with BOP like Macaw's mods. Some of the things even popping up in the world too tried disabling, but made no sense cause even vanilla things are spawning. I've included a modlist of all the mods on my server that maybe will help. I'm not sure if it's something spawning the things or what? I'm really at a loss.
https://mclo.gs/sChyhoY
https://mclo.gs/sChyhoY
