biomes in custom dimension spawn outside their defined ranges?

I've been struggling to get my biomes to generate the way i want them to in my custom dimension for the longest time, and i realised recently that part of the issue is that the biomes are generating beyond their continentalness ranges? For example, ocean biomes spawning on land while forest biomes are spawning in the place of oceans.

For example, this is meant to be an underwater kelp forest biome, but it is also generating as large landmasses above water. It's maximum continentalness is negative, yet it somehow went beyond that.

Another example is this fungus forest, it does spawn on land like it should, but it also stretches far out into the ocean when that's obviously not what i intended.

Does anyone else have this problem? If anyone knows why this is happening or how to solve it please let me know.