Rare crash in M7 P5

[TheDGOfficial]

java.lang.NullPointerException: Cannot invoke "Object.hashCode()" because "key" is null
	at java.base/java.util.concurrent.ConcurrentHashMap.get(ConcurrentHashMap.java:951)
	at java.base/java.util.concurrent.ConcurrentHashMap.getOrDefault(ConcurrentHashMap.java:1621)
	at knot//nofrills.features.dungeons.WitherDragons.onArrowHit(WitherDragons.java:180)
	at knot//meteordevelopment.orbit.listeners.LambdaListener.call(LambdaListener.java:83)
	at knot//meteordevelopment.orbit.EventBus.post(EventBus.java:53)
	at knot//net.minecraft.world.entity.projectile.Projectile.handler$eab000$nofrills$onEntityHit(Projectile.java:523)
	at knot//net.minecraft.world.entity.projectile.Projectile.hitTargetOrDeflectSelf(Projectile.java:225)
	at knot//net.minecraft.world.entity.projectile.arrow.AbstractArrow.hitTargetsOrDeflectSelf(AbstractArrow.java:317)
	at knot//net.minecraft.world.entity.projectile.arrow.AbstractArrow.stepMoveAndHit(AbstractArrow.java:306)
	at knot//net.minecraft.world.entity.projectile.arrow.AbstractArrow.tick(AbstractArrow.java:267)
	at knot//net.minecraft.world.entity.projectile.arrow.Arrow.tick(Arrow.java:78)
	at knot//net.minecraft.client.multiplayer.ClientLevel.tickNonPassenger(ClientLevel.java:346)
	at knot//net.minecraft.world.level.Level.guardEntityTick(Level.java:488)
	at knot//net.minecraft.client.multiplayer.ClientLevel.lambda$tickEntities$0(ClientLevel.java:328)
	at knot//net.minecraft.world.level.entity.EntityTickList.forEach(EntityTickList.java:53)
	at knot//net.minecraft.client.multiplayer.ClientLevel.tickEntities(ClientLevel.java:324)
	at knot//net.minecraft.client.Minecraft.tick(Minecraft.java:1973)
	at knot//net.minecraft.client.Minecraft.runTick(Minecraft.java:1360)
	at knot//net.minecraft.client.Minecraft.run(Minecraft.java:991)
	at java.base/java.lang.Thread.run(Thread.java:1516)