Not sure exactly what causes this, but in certain biomes (namely Oh The Biomes You'll Go - Pointed Stone Forest, or any other BYG biome with the block "byg:overgrown_stone" copper ore from SimpleOres generates rarely. It may have something to do with replacing ores with the forge:stone tag, rather than plain stone because it seems like every vein I find replaces blocks with the tag rather than stone itself.

Minecraft Version: 1.16.5
Forge Version: 36.2.9
SimpleCoreLib Version: 2.0.8.22
SimpleOres2 Version: 2.4.7.2

Latest Log: https://pastebin.com/T8VZxZEb

It may be another mod interfering with SimpleOres ore generation, because not only do I have copper ore generation disabled in the Simpleores config, I also have it set to generate at Y = 1 if by some chance it did generate lol.