Mystic World Advancement Error w/ Amethyst disabled

[19:35:56] [Server thread/ERROR] [FML]: Parsing error loading built-in advancement mysticalworld:amethyst
com.google.gson.JsonSyntaxException: Expected item to be an item, was unknown string 'mysticalworld:amethyst_gem'
	at net.minecraft.util.JsonUtils.getItem(SourceFile:124) ~[rc.class:?]
	at net.minecraft.util.JsonUtils.getItem(SourceFile:135) ~[rc.class:?]
	at net.minecraft.advancements.DisplayInfo.deserializeIcon(DisplayInfo.java:133) ~[r.class:?]
	at net.minecraft.advancements.DisplayInfo.deserialize(DisplayInfo.java:111) ~[r.class:?]
	at net.minecraft.advancements.Advancement$Builder.deserialize(SourceFile:202) ~[i$a.class:?]
	at net.minecraft.advancements.AdvancementManager$1.deserialize(AdvancementManager.java:50) ~[ns$1.class:?]
	at net.minecraft.advancements.AdvancementManager$1.deserialize(AdvancementManager.java:46) ~[ns$1.class:?]
	at com.google.gson.internal.bind.TreeTypeAdapter.read(TreeTypeAdapter.java:69) ~[TreeTypeAdapter.class:?]
	at net.minecraft.util.JsonUtils.gsonDeserialize(SourceFile:492) ~[rc.class:?]
	at net.minecraft.util.JsonUtils.fromJson(SourceFile:532) ~[rc.class:?]
	at net.minecraftforge.common.ForgeHooks.lambda$loadAdvancements$0(ForgeHooks.java:1369) ~[ForgeHooks.class:?]
	at net.minecraftforge.common.crafting.CraftingHelper.findFiles(CraftingHelper.java:821) [CraftingHelper.class:?]
	at net.minecraftforge.common.ForgeHooks.loadAdvancements(ForgeHooks.java:1351) [ForgeHooks.class:?]
	at net.minecraftforge.common.ForgeHooks.loadAdvancements(ForgeHooks.java:1325) [ForgeHooks.class:?]
	at net.minecraft.advancements.AdvancementManager.reload(AdvancementManager.java:69) [ns.class:?]
	at net.minecraft.server.MinecraftServer.reload(MinecraftServer.java:1429) [MinecraftServer.class:?]
	at com.feed_the_beast.ftblib.lib.data.FTBLibAPI.reloadServer(FTBLibAPI.java:105) [FTBLibAPI.class:?]
	at com.feed_the_beast.ftblib.lib.data.Universe.load(Universe.java:524) [Universe.class:?]
	at com.feed_the_beast.ftblib.lib.data.Universe.onWorldLoaded(Universe.java:131) [Universe.class:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_629_Universe_onWorldLoaded_Load.invoke(.dynamic) [?:?]
	at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) [ASMEventHandler.class:?]
	at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) [EventBus.class:?]
	at net.minecraft.server.integrated.IntegratedServer.loadAllWorlds(IntegratedServer.java:132) [chd.class:?]
	at net.minecraft.server.integrated.IntegratedServer.init(IntegratedServer.java:156) [chd.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:486) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:748) [?:1.8.0_212-8u]