I've tried everything as well and it won't budge
Surface, underground and caverns layer;
Regular, ice biome, jungle biome, mushroom biome;
In between 200 and 0 Surface, 0 and 200 Underground, around 400 Caverns;
100+ regular torches, 100+ ultrabright, 100+ mixed torches;
1.4.0.1 world, 1.4.0.3...