WORLDGUARD-2555 - Reported by Roope.Salmi

Whenever someone loads a new chunk, this SEVERE appears in the console and lags the server(Sometimes causes "Can't keep up! ..."):
17:30:30 [SEVERE] Could not pass event BlockFromToEvent to WorldGuard v784-f2d71
35
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:427)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62)
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:477)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:462)
at net.minecraft.server.v1_4_R1.BlockFlowing.b(BlockFlowing.java:145)
at net.minecraft.server.v1_4_R1.WorldGenLiquids.a(SourceFile:37)
at net.minecraft.server.v1_4_R1.BiomeDecorator.a(SourceFile:206)
at net.minecraft.server.v1_4_R1.BiomeDecorator.a(SourceFile:27)
at net.minecraft.server.v1_4_R1.BiomeBase.a(SourceFile:217)
at net.minecraft.server.v1_4_R1.BiomeBigHills.a(SourceFile:21)
at net.minecraft.server.v1_4_R1.ChunkProviderGenerate.getChunkAt(SourceF
ile:450)
at org.bukkit.craftbukkit.v1_4_R1.generator.NormalChunkGenerator.getChun
kAt(NormalChunkGenerator.java:49)
at net.minecraft.server.v1_4_R1.ChunkProviderServer.getChunkAt(ChunkProv
iderServer.java:226)
at net.minecraft.server.v1_4_R1.Chunk.a(Chunk.java:789)
at org.bukkit.craftbukkit.v1_4_R1.chunkio.ChunkIOProvider.callStage2(Chu
nkIOProvider.java:61)
at org.bukkit.craftbukkit.v1_4_R1.chunkio.ChunkIOProvider.callStage2(Chu
nkIOProvider.java:13)
at org.bukkit.craftbukkit.v1_4_R1.util.AsynchronousExecutor$Task.finish(
AsynchronousExecutor.java:179)
at org.bukkit.craftbukkit.v1_4_R1.util.AsynchronousExecutor.finishActive
(AsynchronousExecutor.java:287)
at org.bukkit.craftbukkit.v1_4_R1.chunkio.ChunkIOExecutor.tick(ChunkIOEx
ecutor.java:30)
at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:5
37)
at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:2
24)
at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:4
94)
at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java
:427)
at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:8
49)
Caused by: java.lang.RuntimeException: Already decorating!!
at net.minecraft.server.v1_4_R1.BiomeDecorator.a(SourceFile:21)
at net.minecraft.server.v1_4_R1.BiomeBase.a(SourceFile:217)
at net.minecraft.server.v1_4_R1.BiomeBigHills.a(SourceFile:21)
at net.minecraft.server.v1_4_R1.ChunkProviderGenerate.getChunkAt(SourceF
ile:450)
at org.bukkit.craftbukkit.v1_4_R1.generator.NormalChunkGenerator.getChun
kAt(NormalChunkGenerator.java:49)
at net.minecraft.server.v1_4_R1.ChunkProviderServer.getChunkAt(ChunkProv
iderServer.java:226)
at net.minecraft.server.v1_4_R1.Chunk.a(Chunk.java:797)
at net.minecraft.server.v1_4_R1.ChunkProviderServer.getChunkAt(ChunkProv
iderServer.java:143)
at net.minecraft.server.v1_4_R1.ChunkProviderServer.getChunkAt(ChunkProv
iderServer.java:85)
at org.bukkit.craftbukkit.v1_4_R1.CraftWorld.getChunkAt(CraftWorld.java:
117)
at org.bukkit.craftbukkit.v1_4_R1.CraftWorld.getBlockAt(CraftWorld.java:
81)
at com.sk89q.worldguard.bukkit.WorldGuardBlockListener.onBlockFromTo(Wor
ldGuardBlockListener.java:208)
at sun.reflect.GeneratedMethodAccessor440.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:425)
... 23 more

Is this maybe caused by bukkit?

Comment by wizjany

caused by bukkit being silly with events, nothing we can do

not sure why you're getting it so much though, do you have the water/lava flow flags on?
maybe high-freq flags?