Strange Biome Generation

I'm making a custom dimension mod and have noticed that the biomes are generating strangely small and splotchy. What I mean by this is that rather than a big forest, there may be a small patch between two different other biomes, or a small forest in the middle of a donut-shaped mountains biome. Additionally, a lot of biomes seem to form longer shapes rather than wider ones, as if they are very short rivers. All biomes are custom, no vanilla biomes in the mix. 

There also seems to be a weird ratio of biomes. I'm seeing a biome with a weight of 5 or so about as often as a biome with a weight of 20. Could this be a biome weight bug? Stuff generated a lot more how one would expect in another Dimension mod I made before. Could this be an issue with the newest snapshot version of mcreator? Could it be an issue with my biome weight settings? I deparented all parented biomes to see if that would help but it did not. In fact, it still feels as if the deparented biome is still parented.