Hello I downloaded this mod recently and I noticed that they had a biome the Cursed Forest, I deactivated the biome with a 0 like what is marked in the config, except that in game the biome always spawn.

mod version :
1.12.2-0.5.4

This is an issue with the GUI config with the 1.12.2 version of this mod which as of right now is currently not receiving updates. A workaround is to edit the config file manually in .minecraft/config/herobrine-common.cfg