I've also noticed only a single problematic bug in my hours of playing the mod. Seems that armor materials added to the config are still not entirely recognized by the mod. They'll display the appropriate armor class on the tooltip but if you try to put them on while playing a class that should be able to wear them, they'll just be taken off immediately. If you you shift click them on, they'll stay but then duplicate the armor. Pretty strange!

I'm trying to add an armor mat to the config, but it doesn't seem like I'm matching the format mkultra is looking for.

Tried several variations of the material's name (ebwizardry:magic_silk, silk, SILK, ...) but end up with

Failed to find armor material from config, SILK

This is from ebwizardry; after looking at the mku config code, I figured it is looking for this name:
public static final ArmorMaterial SILK = EnumHelper.addArmorMaterial("SILK", "wizardry/textures/armour/wizard_armour", 15, new int[]{0, 0, 0, 0}, 0, SoundEvents.ITEM_ARMOR_EQUIP_LEATHER, 0.0F);

this is super odd, I'll have to investigate further as we have several other armors that use enum names like this and they seemed to work.