On load.
https://paste.gg/p/anonymous/08deb5411fd349a58f6be6bc3defba88

Do you have any modules disabled? It looks like the hell infusion enchantment doesnt exist, but the hellshelf still does.

Only what's default. Haven't touched configs yet. Looking.

All modules are enabled.

Thats rather interesting. I imagine something else is causing the error to happen, as it launches fine on it's own, and is in ATM4 with no known issues

Possible. Leaving disabled for the moment. Will re-enable if updated before error found and test again.

found the conflicting mod: betterTotem1.0-1.14.4

Then it would be a bug in that mod, likely for invoking getSubItems before registry phase has ended.