When this mod is added with the other mod, that mod will not work (won't generate light)
If more info is needed, do ask for more as I do not really know what I should add.. Sorry

Post the full debug.log. What is this "other mod"

https://www.curseforge.com/minecraft/mc-mods/smooth-entity-light , It's a mod that add's dynamic light to torches and such, I am planning on using it with Hardcore Darkness.

Debug.log : https://controlc.com/5f03f69b

1.12 is no longer supported.