Hello, I know this is a duplication of another. I read #266 and have read that it could be a possibility of a corrupted world, but I don't think this is the case. Just like #266 but I use Optifine to help render some things and to increase my FPS since this modpack has some of the big mods. I had this error before a few weeks back on a server that I play on with a few of my friends. Since those past weeks, I haven't gotten this error once. But now, my friends have been experiencing this error and I haven't these few weeks. The error I have pasted below came from an old crash log I had. I uploaded the complete log to Pastebin just in case.

java.lang.ArrayIndexOutOfBoundsException: 2
    at powercrystals.minefactoryreloaded.block.BlockRubberLeaves.func_149691_a(BlockRubberLeaves.java:65)
    at powercrystals.minefactoryreloaded.block.BlockRubberLeaves.func_149673_e(BlockRubberLeaves.java:58)
    at net.minecraft.client.renderer.RenderBlocks.func_147793_a(RenderBlocks.java:9361)
    at net.minecraft.client.renderer.RenderBlocks.func_147736_d(RenderBlocks.java:6562)
    at net.minecraft.client.renderer.RenderBlocks.func_147784_q(RenderBlocks.java:4716)
    at net.minecraft.client.renderer.RenderBlocks.func_147805_b(RenderBlocks.java:307)
    at net.minecraft.client.renderer.WorldRenderer.func_147892_a(WorldRenderer.java:320)
    at net.minecraft.client.renderer.RenderGlobal.func_72716_a(RenderGlobal.java:2245)
    at net.minecraft.client.renderer.EntityRenderer.func_78471_a(EntityRenderer.java:1513)
    at net.minecraft.client.renderer.EntityRenderer.func_78480_b(EntityRenderer.java:1304)
    at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1001)
    at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:898)
    at net.minecraft.client.main.Main.main(SourceFile:148)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
    at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:310)
    at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:394)
    at org.multimc.EntryPoint.listen(EntryPoint.java:170)
    at org.multimc.EntryPoint.main(EntryPoint.java:54)

Here's the settings I currently have set to Optifine: Pastebin
I had everything enabled on Optifine, then I started crashing. I then started turning everything off and then I stopped crashing when I turned off "Load Far." It seems that was the problem, but I'm not 100% certain if this is the setting that was causing the crash.

EDIT: Deleted Optionsof.txt to regenerate with default settings, will report back later.
EDIT2: It crashed with "Load Far" on, so now I'm going to turn it off and see what will happen. If how long it took for the error to be given be any of interest; I joined the server at 15:55 my time and crashed at 15:59, takes 4 minutes to register the crash.
EDIT3: Still crashed, took the same amount of time to crash. Will have to change some more settings to find out what's actually causing the crash. I'm thinking it's the settings called "Better Grass" and settings have to do with biomes might also be the cause, so I'll disable those next.
EDIT4: Changed Detail/Grass to Fast, Quality/Swamp Colors to Off, Quality/Smooth Biomes to off, hopefully that'll stop the crashing.
EDIT5: Nope, Still crashed and the same amount of minutes as the first and second crash...
EDIT6: Okay... I turned down my render distance to 2 and that stopped the crash. It could be a combination of all the settings I have listed

If it is optifine, then it should not be altering mod's block data. Disable everything related to 'enhancing' vanilla like connected textures and see if it persists.

Well... After countless days after removing the mod, opening the server, shutting it down and adding it back stopped the crash... Quite strange...