Structures not spawning at all

I've been updating my mod from 2021.2 to 2022.1 and it's not been slick. I had a biome that spawned dozens of structures that were like the giant mushrooms from vanilla MC but with my custom blocks, and they were basically the biome's trademark feature. But ever since I've updated the mod, these mushrooms are gone. I've increased their ammount per chunk countless times and they never spawn, not even at 400,000 per chunk. But, weirdly enough, once I create a single biome world with this biome specifically, they work perfectly fine.

Following is one of their spawn settings (there's 3 types but they all spawn the same way). You may realize they can spawn underwater but that's intentional, don't worry.