Passing mods (modules) as mods to forge's --modListFile are not being picked up by Charset's module loader. Support should be added and backported to any supported versions.

See: https://github.com/MinecraftForge/MinecraftForge/blob/1.12.x/src/main/java/net/minecraftforge/fml/relauncher/libraries/ModList.java

cc @TheFlash787

That... explains quite a lot, actually. However, I am already using the ASMDataTable to query the list of loaded modules, which should be processing every mod loaded. Unless I'm doing the lookup too early, that is - I haven't looked into the modlist functionality very much, admittedly.