Something I've discovered in a modpack I'm working on is that when I go into the mod config and disable certain armor sets for balancing reasons, doing so results in the smithing table losing most of it's functionality. Specifically, it only becomes able to accept diamond equipment and it can only be used to upgrade it into netherite. You're still able to put in armor trim templates and appropriate gems/metals, but you cannot place in any non-diamond armor nor utilize any trim templates, even if you're trying to trim diamond armor. I have tested this on a separate world with no other mods and the issue still persists.

Mod version is 1.6.1, forge is 47.2.20

latest.log

I assume that this happens when client and server config do not match? In any case, configurable armor will get removed most likely, its a hacky feature not compatible with how Minecraft works.

Well, I'm having the issue on a pure single-player world, I don't know why the client/server configs wouldn't match.

Then I will declare this config flag as deprecated right away, don't use it.