The quest for the healing axe, you need 16 rainbow curry. One of the items you need for it is a lavender flower from Biomes O Plenty. I've crafted the Nature's Compass to find a lavender biome, however it locks up server chunk generation for ~5 seconds and comes up with "Not Found" in a radius of 10,000 blocks. I'm not sure if they are actually this rare as the whole minecraft world is only 60k by 60k blocks, and this biome didn't spawn in 10k blocks in any direction from spawn.
EDIT: Just found out that the server properties has the LEVEL_TYPE set to default, by default. Not sure why because from my findings lavender only spawns in BOP biomes, and it should be set to it by default, otherwise the healing axe is impossible to get through the quest, and rainbow curry impossible to get at all. I would change it but my world has already been generated for almost two weeks and I don't prefer to start all over again. I could simply just spawn this in but I can't on the other public server I play on.