https://github.com/MinecraftForge/MinecraftForge/blob/1.15.x/src/fmllauncher/java/net/minecraftforge/fml/loading/moddiscovery/ModFileParser.java I'm experiencing this both in the old Java launcher and in GDLauncher 0.12.4. Image: https://imgur.com/gallery/XQbCaf1 debug.log from Java launcher...