[16:48:09] [Server thread/ERROR]: Encountered an unexpected exception
net.minecraft.server.v1_8_R3.ReportedException: Exception ticking world
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:781) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot.jar:git-Spigot-db6de12-18fbb24]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]
Caused by: java.util.ConcurrentModificationException
	at org.bukkit.craftbukkit.v1_8_R3.util.LongObjectHashMap$ValueIterator.next(LongObjectHashMap.java:297) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at org.bukkit.craftbukkit.v1_8_R3.CraftWorld.processChunkGC(CraftWorld.java:1374) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.WorldServer.doTick(WorldServer.java:272) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:770) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	... 4 more
[16:48:09] [Server thread/ERROR]: 	Cause of unexpected exception was
java.util.ConcurrentModificationException
	at org.bukkit.craftbukkit.v1_8_R3.util.LongObjectHashMap$ValueIterator.next(LongObjectHashMap.java:297) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at org.bukkit.craftbukkit.v1_8_R3.CraftWorld.processChunkGC(CraftWorld.java:1374) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.WorldServer.doTick(WorldServer.java:272) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:770) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) ~[spigot.jar:git-Spigot-db6de12-18fbb24]
	at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot.jar:git-Spigot-db6de12-18fbb24]
	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_91]