net.minecraft.util.ReportedException: Exception ticking world
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:776) ~[MinecraftServer.class:?]
	at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:685) ~[MinecraftServer.class:?]
	at net.minecraft.server.integrated.IntegratedServer.tick(IntegratedServer.java:155) ~[IntegratedServer.class:?]
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:534) [MinecraftServer.class:?]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]
Caused by: java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429) ~[?:1.8.0_91]
	at java.util.HashMap$ValueIterator.next(HashMap.java:1458) ~[?:1.8.0_91]
	at java.util.Collections$UnmodifiableCollection$1.next(Collections.java:1042) ~[?:1.8.0_91]
	at cubicchunks.server.ServerCubeCache.unloadQueuedChunks(ServerCubeCache.java:279) ~[ServerCubeCache.class:?]
	at net.minecraft.world.WorldServer.tick(WorldServer.java:209) ~[WorldServer.class:?]
	at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:770) ~[MinecraftServer.class:?]
	... 4 more