A crash while saving NBT

[MorningMC]

CompoundTag config = new CompoundTag();
		
		config.put("globalSettings", GlobalSettings.loader.save(GlobalSettings.instance));
		config.put("profileCollection", ProfileCollection.loader.save(ProfileCollection.instance));
		config.put("javaRuntimeCollection", JavaRuntimeCollection.loader.save(JavaRuntimeCollection.instance));
		config.put("launcher", Launcher.loader.save(launcher));
		config.put("translation", Translation.loader.save(Translation.instance));
		
		try {
			new Nbt().toFile(config, FileMetadata.config); // Crashed here
		} catch (Exception e) {
			logger.error("Failed to save config: ", e);
		}

Stacktrace:

java.lang.NullPointerException: Cannot read field "next" because "this.next" is null
	at java.util.LinkedList$ListItr.next(LinkedList.java:904) ~[?:?]
	at dev.dewy.nbt.tags.collection.ListTag.write(ListTag.java:109) ~[nbt-1.5.1.jar:?]
	at dev.dewy.nbt.tags.collection.CompoundTag.write(CompoundTag.java:92) ~[nbt-1.5.1.jar:?]
	at dev.dewy.nbt.io.NbtWriter.toStream(NbtWriter.java:37) ~[nbt-1.5.1.jar:?]
	at dev.dewy.nbt.Nbt.toStream(Nbt.java:85) ~[nbt-1.5.1.jar:?]
	at dev.dewy.nbt.Nbt.toFile(Nbt.java:122) ~[nbt-1.5.1.jar:?]
	at dev.dewy.nbt.Nbt.toFile(Nbt.java:96) ~[nbt-1.5.1.jar:?]
	at minecraft.morningmc.mcli.launcher.main.Main.stop(Main.java:132) ~[classes/:?]
	at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$10(LauncherImpl.java:858) ~[javafx-graphics-21-win.jar:?]
	at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:483) ~[javafx-graphics-21-win.jar:?]
	at com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:456) ~[javafx-graphics-21-win.jar:?]
	at java.security.AccessController.doPrivileged(AccessController.java:400) ~[?:?]
	at com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:455) ~[javafx-graphics-21-win.jar:?]
	at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95) ~[javafx-graphics-21-win.jar:?]
	at com.sun.glass.ui.win.WinApplication._runLoop(Native Method) ~[javafx-graphics-21-win.jar:?]
	at com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:185) ~[javafx-graphics-21-win.jar:?]
	at java.lang.Thread.run(Thread.java:1583) ~[?:?]