What's the issue you encountered?

Specific surface rules - I don't particularly see any rhyme or reason to why - break only when TerraBlender is installed. Vanilla datagen shouldn't be conflicting with a mod like this to this extent, especially when the core purpose of TerraBlender is to help with adding biomes, and surface rules are there instead to help with generating terrain materials.

There is no crashing involved, but I would consider this a major breaking change as it breaks existing APIs.

How can the issue be reproduced?

There isn't exactly a methodology I've tested. All I know is, if I create a class which is a copy-paste of vanilla's overworld surface rules and make edits to it on a per-biome basis for normal stone and deepslate generation, I encounter functionality breaks when TerraBlender is installed and only when TerraBlender is installed. Removing it from my gradle and toml files reverts functionality back to what is expected.

Logs

No response

Mod Version

4.1.0.8

Additional information

latest v1.21.1, Neoforged