[17w49b] Client thread/FATAL: Non [a-z0-9/._-] character in path of location

Client crashes when typing "/function custom:veritas0923:" as soon as second : is typed Minecraft CTD.

This is consistent on my current world. Have not tried on a fresh world yet.
–

[03:00:50] [Server thread/INFO]: Saving chunks for level '17w49b Offline Dec 2017'/overworld
[03:00:51] [Client thread/FATAL]: Reported exception thrown!
f: charTyped event handler
	at bqq.a(SourceFile:433) ~[minecraft-17w49b-client.jar:?]
	at bmw.a(SourceFile:360) ~[minecraft-17w49b-client.jar:?]
	at org.lwjgl.glfw.GLFWCharModsCallbackI.callback(GLFWCharModsCallbackI.java:23) ~[lwjgl-glfw-3.1.2.jar:?]
	at org.lwjgl.system.JNI.invokeV(Native Method) ~[lwjgl-3.1.2.jar:?]
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:2520) ~[lwjgl-glfw-3.1.2.jar:?]
	at bnj.a(SourceFile:282) ~[minecraft-17w49b-client.jar:?]
	at bmz.b(SourceFile:846) ~[minecraft-17w49b-client.jar:?]
	at bmz.a(SourceFile:380) [minecraft-17w49b-client.jar:?]
	at net.minecraft.client.main.Main.main(SourceFile:140) [minecraft-17w49b-client.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_151]
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_151]
	at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_151]
	at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [NewLaunch.jar:?]
	at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [NewLaunch.jar:?]
	at org.multimc.EntryPoint.listen(EntryPoint.java:143) [NewLaunch.jar:?]
	at org.multimc.EntryPoint.main(EntryPoint.java:34) [NewLaunch.jar:?]
Caused by: g: Non [a-z0-9/._-] character in path of location: custom:veritas0923:
	at mw.<init>(SourceFile:32) ~[minecraft-17w49b-client.jar:?]
	at mw.<init>(SourceFile:37) ~[minecraft-17w49b-client.jar:?]
	at mw.a(SourceFile:122) ~[minecraft-17w49b-client.jar:?]
	at cu.a(SourceFile:42) ~[minecraft-17w49b-client.jar:?]
	at cu.parse(SourceFile:20) ~[minecraft-17w49b-client.jar:?]
	at com.mojang.brigadier.tree.ArgumentCommandNode.parse(ArgumentCommandNode.java:55) ~[brigadier-0.1.13.jar:?]
	at com.mojang.brigadier.CommandDispatcher.parseNodes(CommandDispatcher.java:169) ~[brigadier-0.1.13.jar:?]
	at com.mojang.brigadier.CommandDispatcher.parseNodes(CommandDispatcher.java:191) ~[brigadier-0.1.13.jar:?]
	at com.mojang.brigadier.CommandDispatcher.parse(CommandDispatcher.java:143) ~[brigadier-0.1.13.jar:?]
	at bpt.h(SourceFile:160) ~[minecraft-17w49b-client.jar:?]
	at bpt.a(SourceFile:96) ~[minecraft-17w49b-client.jar:?]
	at boe.a(SourceFile:146) ~[minecraft-17w49b-client.jar:?]
	at boe.b(SourceFile:141) ~[minecraft-17w49b-client.jar:?]
	at boe.charTyped(SourceFile:375) ~[minecraft-17w49b-client.jar:?]
	at boy.charTyped(SourceFile:40) ~[minecraft-17w49b-client.jar:?]
	at bmw.a(SourceFile:360) ~[minecraft-17w49b-client.jar:?]
	at bqq.a(SourceFile:428) ~[minecraft-17w49b-client.jar:?]
	... 16 more
---- Minecraft Crash Report ----
// You're mean.

Time: 12/10/17 3:00 AM
Description: charTyped event handler

g: Non [a-z0-9/._-] character in path of location: custom:veritas0923:
	at mw.<init>(SourceFile:32)
	at mw.<init>(SourceFile:37)
	at mw.a(SourceFile:122)
	at cu.a(SourceFile:42)
	at cu.parse(SourceFile:20)
	at com.mojang.brigadier.tree.ArgumentCommandNode.parse(ArgumentCommandNode.java:55)
	at com.mojang.brigadier.CommandDispatcher.parseNodes(CommandDispatcher.java:169)
	at com.mojang.brigadier.CommandDispatcher.parseNodes(CommandDispatcher.java:191)
	at com.mojang.brigadier.CommandDispatcher.parse(CommandDispatcher.java:143)
	at bpt.h(SourceFile:160)
	at bpt.a(SourceFile:96)
	at boe.a(SourceFile:146)
	at boe.b(SourceFile:141)
	at boe.charTyped(SourceFile:375)
	at boy.charTyped(SourceFile:40)
	at bmw.a(SourceFile:360)
	at bqq.a(SourceFile:428)
	at bmw.a(SourceFile:360)
	at org.lwjgl.glfw.GLFWCharModsCallbackI.callback(GLFWCharModsCallbackI.java:23)
	at org.lwjgl.system.JNI.invokeV(Native Method)
	at org.lwjgl.glfw.GLFW.glfwPollEvents(GLFW.java:2520)
	at bnj.a(SourceFile:282)
	at bmz.b(SourceFile:846)
	at bmz.a(SourceFile:380)
	at net.minecraft.client.main.Main.main(SourceFile:140)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196)
	at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231)
	at org.multimc.EntryPoint.listen(EntryPoint.java:143)
	at org.multimc.EntryPoint.main(EntryPoint.java:34)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Thread: Client thread
Stacktrace:
	at mw.<init>(SourceFile:32)
	at mw.<init>(SourceFile:37)
	at mw.a(SourceFile:122)
	at cu.a(SourceFile:42)
	at cu.parse(SourceFile:20)
	at com.mojang.brigadier.tree.ArgumentCommandNode.parse(ArgumentCommandNode.java:55)
	at com.mojang.brigadier.CommandDispatcher.parseNodes(CommandDispatcher.java:169)
	at com.mojang.brigadier.CommandDispatcher.parseNodes(CommandDispatcher.java:191)
	at com.mojang.brigadier.CommandDispatcher.parse(CommandDispatcher.java:143)
	at bpt.h(SourceFile:160)
	at bpt.a(SourceFile:96)
	at boe.a(SourceFile:146)
	at boe.b(SourceFile:141)
	at boe.charTyped(SourceFile:375)
	at boy.charTyped(SourceFile:40)
	at bmw.a(SourceFile:360)