Here's the stack trace for it:

 

[02:49:10] [Client thread/FATAL]: Error executing task
java.util.concurrent.ExecutionException: java.lang.IllegalArgumentException: Default value cannot be lower than minimum value!
at java.util.concurrent.FutureTask.report(Unknown Source) ~[?:1.8.0_91]
at java.util.concurrent.FutureTask.get(Unknown Source) ~[?:1.8.0_91]
at net.minecraft.util.Util.func_181617_a(SourceFile:46) [g.class:?]
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1041) [bcf.class:?]
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:366) [bcf.class:?]
at net.minecraft.client.main.Main.main(SourceFile:124) [Main.class:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_91]
at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_91]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
Caused by: java.lang.IllegalArgumentException: Default value cannot be lower than minimum value!
at net.minecraft.entity.ai.attributes.RangedAttribute.<init>(SourceFile:21) ~[ss.class:?]
at net.minecraft.client.network.NetHandlerPlayClient.func_147290_a(NetHandlerPlayClient.java:1963) ~[bks.class:?]
at net.minecraft.network.play.server.SPacketEntityProperties.func_148833_a(SourceFile:70) ~[id.class:?]
at net.minecraft.network.play.server.SPacketEntityProperties.func_148833_a(SourceFile:15) ~[id.class:?]
at net.minecraft.network.PacketThreadUtil$1.run(SourceFile:13) ~[fh$1.class:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) ~[?:1.8.0_91]
at java.util.concurrent.FutureTask.run(Unknown Source) ~[?:1.8.0_91]
at net.minecraft.util.Util.func_181617_a(SourceFile:45) ~[g.class:?]
... 9 more

 

 

 

Please, don't let this stay in past the beta builds.. I can't read my console at all and my log sizes have went up 10 times as much (minimum).

 

Forge Build: 1887 (Latest version at time of posting. Build 1886, and 1865 have this issue, other versions were not tested)

Minecraft version: 1.9

 

No mods are installed.

 

This occurs while walking around in a server, it doesn't appear to happen in Single Player

 

 

Also:

It seems every colon is now overly escaped:

 

 

Not reproducible in any way...

You need to try and figure out a way to reproduce.

This is usually caused by corrupt worlds or mods that break entity AI.

Really? It seems every server I go to has this issue, and I have no mods other than forge mod loader enabled just to test when that log was created and screenshot was taken.

 

How did you try testing it? I tried on a local spigot 1.9.2 server and here's the output of the version command.

 

[18:09:50 INFO]: This server is running CraftBukkit version git-Spigot-5a40365-b70058a (MC: 1.9.2) (Implementing API version 1.9.2-R0.1-SNAPSHOT)
[18:09:50 INFO]: Checking version, please wait...
[18:09:51 INFO]: You are 15 version(s) behind

 

Thanks for the help so far and sorry it seems to have been a waste

Most likely a spigot issue then.

The server is sending invalid config options for the entities' AI values.

 

Ah, alright thanks Lex I'll see about submitting a bug report with them then? Is there a fix I can do in the mean time? Like I noticed FML recently enabled FutureTask error logging like that, is there a clientside way to disable it or anything?

The logging is important, you need to get these issues fixed, it's not on our end.

I have those doubly escaped colons too.

Yes it's a localization issue from crowdin. Nobody really cares. It'll be fixed eventually.