java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextEntry(HashMap.java:922)
	at java.util.HashMap$KeyIterator.next(HashMap.java:956)
	at org.bukkit.permissions.PermissibleBase.clearPermissions(PermissibleBase.java:168)
	at org.bukkit.permissions.PermissibleBase.recalculatePermissions(PermissibleBase.java:149)
	at org.bukkit.craftbukkit.v1_10_R1.entity.CraftHumanEntity.recalculatePermissions(CraftHumanEntity.java:137)
	at net.minecraft.server.v1_10_R1.PlayerList.removeOp(PlayerList.java:1111)
	at net.minecraft.server.v1_10_R1.DedicatedPlayerList.removeOp(SourceFile:52)
	at org.bukkit.craftbukkit.v1_10_R1.entity.CraftPlayer.setOp(CraftPlayer.java:103)
	at com.nisovin.magicspells.spells.ExternalCommandSpell.process(ExternalCommandSpell.java:214)
	at com.nisovin.magicspells.spells.ExternalCommandSpell.castSpell(ExternalCommandSpell.java:112)
	at com.nisovin.magicspells.Spell.handleCast(Spell.java:1283)
	at com.nisovin.magicspells.Spell.cast(Spell.java:1207)
	at com.nisovin.magicspells.Spell.cast(Spell.java:1196)
	at com.nisovin.magicspells.CastCommand.onCommand(CastCommand.java:65)
	at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
	at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141)
	at org.bukkit.craftbukkit.v1_10_R1.CraftServer.dispatchCommand(CraftServer.java:647)
	at com.mewin.wgrc.RegionListener.parseCmd(RegionListener.java:65)
	at com.mewin.wgrc.RegionListener.onRegionEntered(RegionListener.java:48)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302)
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
	at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487)
	at com.mewin.WGRegionEvents.WGRegionEventsListener$1.run(WGRegionEventsListener.java:147)
	at org.bukkit.craftbukkit.v1_10_R1.scheduler.CraftTask.run(CraftTask.java:71)
	at org.bukkit.craftbukkit.v1_10_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:353)
	at net.minecraft.server.v1_10_R1.MinecraftServer.D(MinecraftServer.java:723)
	at net.minecraft.server.v1_10_R1.DedicatedServer.D(DedicatedServer.java:400)
	at net.minecraft.server.v1_10_R1.MinecraftServer.C(MinecraftServer.java:668)
	at net.minecraft.server.v1_10_R1.MinecraftServer.run(MinecraftServer.java:567)
	at java.lang.Thread.run(Thread.java:745)

Server version: git-Spigot-de459a2-51263e9 (MC: 1.10.2)
MagicSpells version: 3.5-dev-1611020619