Versions:
Minecraft: 1.20.1
Forge: 47.3.4
NatProg: 2.3.8

Logs:
https://gist.github.com/CraftyZombie/9421a63acb2cf36d08ef30413d7bb286

Config:
Unaltered.

Description:
I've noticed that in 2.3.8 (I don't remember about 2.3.7), pebbles and twigs will only spawn underwater. I've checked everywhere for them. The rest of the world is completely barren. Downgrading to 2.3.6 makes pebbles spawn elsewhere again. There's no way it's a coincidence, but I don't know the cause of it either.

The exact same issue here as well. Reverting to 2.3.7 fixes the no pebble world generation issue.

The same error happens to me, Pebbles and twigs are not generated on the surface and only under water.

also experiencing the same issue. All pebbles / twigs only exist under water.

Forge / 1.20.1-47.3.7

If I downgrade to 2.3.7 there is a conflict with Silent Gear where even when the Tool Neutering is set to "False" it neuters the Silent Tools.