As explained in detail in: BlakeBr0/MysticalAgradditions#62 , unregistered ConfiguredFeatures should be registered to prevent mod incompatibility issues

Here's what the unregistered ConfiguredFeature's json had to help narrow down what ConfiguredFeature needs to be registered in this mod:
mysticalagriculture:inferium_ore
mysticalagriculture:prosperity_ore
mysticalagriculture:soulstone

Hope this helps!