What version are you using?

darkness-forge-1.12.x-0.4.2.

Does this issue reproduce with the latest release?

Read above.

Which other mods do you have installed?

Quite a few. Dynamic Darkness is a client mod, so most of the stuff I have wouldn't affect it. I hope.

What did you do?

Run the game.

What did you expect to see?

Caves being pitch black.

What did you see instead?

I did not make any config changes.