Changing light output on block crashing game

I am creating a mod that has a block that has several different light emission levels (depending on the blockstate of the block it will glow with different amounts of light).

However I am having an issue where if the block's light changes too rapidly (like more than twice a second or something) the game throws a ConcurrentModificationException and crashes.

Error StackTrace:

java.util.ConcurrentModificationException: null
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445) ~[?:1.8.0_222]
	at java.util.HashMap$KeyIterator.next(HashMap.java:1469) ~[?:1.8.0_222]
	at net.minecraft.client.renderer.RenderGlobal.updateClouds(RenderGlobal.java:1244) ~[RenderGlobal.class:?]
	at net.minecraft.client.Minecraft.runTick(Minecraft.java:1961) ~[Minecraft.class:?]
	at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1187) ~[Minecraft.class:?]
	at net.minecraft.client.Minecraft.run(Minecraft.java:441) [Minecraft.class:?]
	at net.minecraft.client.main.Main.main(Main.java:118) [Main.class:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_222]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_222]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_222]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_222]
	at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
	at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_222]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_222]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_222]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_222]
	at net.minecraftforge.gradle.GradleStartCommon.launch(GradleStartCommon.java:97) [start/:?]
	at GradleStart.main(GradleStart.java:25) [start/:?]

If I set the light output to a fixed level, it operates fine. I have tried invoking the light updates when the state changes but that has not seemed to change anything.