Forge version: 1.12.2-14.23.5.2838
Twilight Forest version: 1.12.2-3.9.984
Link to crash log: https://pastebin.com/raw/2gAeVYTd

Steps to reproduce:

1. Download last version
2. Start server.
3. See errors on startup.

What I expected to happen:
If i dont use some of the supported mods, there should be no errors.

What happened instead:
Errors in the console.

Since Forge has no support for optional advancement loading unlike recipes, we’re not able to prevent these errors from appearing on your console. However the game will function just fine.

this is a problem with your patchouli implementation. seriously a wontfix for errors to display 2 lines on a optional book about an option mod?

There really isn't a fix if Forge does not have the support.

maybe a config to disable expressly an optional mod in the config?
or simply not add 2 lines of text for an optional mod until they add the proper support?
you dont write broken code just because there is no proper support.

Again, there is no fix, and removing those lines will break the mod more than just a couple harmless errors. There already is a "disable mod compatability" config option. Stop trying to suggest solutions to a problem that cannot be fixed on this side because these errors are completely harmless. If you do want a fix, you have to take it up to Forge, or get the optional mods.

This has nothing to do with patchouli at all

See: #753 (comment)