Server freeze after failed Stronghold Placements

Hey, I'm writing a plugin on my test server and it keeps freezing after printing these two lines in the console:

Code:

13:08:06 [INFO] Placed stronghold in INVALID biome at (0, 44)
13:08:06 [INFO] Placed stronghold in INVALID biome at (-49, -29)

I'm sure it has something to do with the BlockIterator class I'm running in a SyncRepeatingTask every 5 ticks. It only freezes after running through it a couple of times.

World seed: -8751858191756862138
Craftbukkit version: git-Bukkit-1.0.1-R1-b1597jnks
(waiting for 1.1 RB before updating)

Thought I'd report it here, but I'm just going to make a new world and see if that fixes it.

 

Believe it or not this is one of the very few bugs in Minecraft. Not bukkit. So there is not much to be able to fix it rather than start a new world i guess?