"Leaking Worlds"

[opa334]

Hi, I play FTB with my friend (LAN) and when I load the World I get an Error in the Console

2013-02-16 11:13:05 [SEVERE] [ForgeModLoader] Detected leaking worlds in memory. There are 4 worlds that appear to be persisting. A mod is likely caching the world incorrectly
 
2013-02-16 11:13:05 [SEVERE] [ForgeModLoader] The world 69751ad (FTB Survival) has leaked.
 
2013-02-16 11:13:05 [SEVERE] [ForgeModLoader] The world 6d8e78c0 (FTB Survival) has leaked.

Is that bad? We already had over 2 Worlds because 1-4 Chunks are not there.
PS: Sorry for my bad english.
The whole Log can be found here:
http://pastebin.com/4n35BqUY

 

[Karimiri]

yeah i had this to, no chunks were missing tho (i hope) and i had only overworld and nether. no mystcraft running.
i wonder if that have something to do with some mods i updated manualy: forestry, ironchest...

edit: or new "temporary" NEI, but thats clientside so dunno...

 

[ChiTown03]

I believe this has to do with either chicken chunks or code chicken core. I seen this problem in another thread, don't know where though.