[1.7.10] Nevermind (DecorateBiomeEvent.Post called recursively?)

EDIT: Nevermind, doesn't seem to be doing it anymore, even though I'm pretty sure I haven't changed anything. If I happen across this again, I'll update this thread.

While messing around, I found something very interesting and somewhat alarming:

Decorating at -1600/0, << shift: -25600/0
// note that the new x/z values are the previous ones bit-shifted!!!
Decorating at -25600/0, << shift: -409600/0
// and again!!!
Decorating at -409600/0, << shift: -6553600/0
Decorating at -1600/-64, << shift: -25600/-1024
Decorating at -25600/-1024, << shift: -409600/-16384
Decorating at -1600/-80, << shift: -25600/-1280
Decorating at -25600/-1280, << shift: -409600/-20480
Decorating at -409600/-20480, << shift: -6553600/-327680

I was checking if DecorateBiomeEvent.Post's chunkX/chunkZ fields were block positions, or chunk positions; the above output was generated by this code:

@SubscribeEvent
public void onDecorate(DecorateBiomeEvent.Post event) {
if (event.world.provider.isSurfaceWorld()) {
	logger.info(String.format("Decorating at %d/%d, << shift: %d/%d",
		event.chunkX, event.chunkZ, (event.chunkX << 4), (event.chunkZ << 4)));
}
}

What's especially interesting is that the output clearly shows that the decorator is called once with block coordinates, but then those exact same block coordinates are << 4 as though they were chunk coordinates and apparently RE-POSTED to the event bus!

Any ideas on why this is? The only places that this event gets posted is from BiomeDecorator#genDecorations and, for the Nether, from ChunkProviderHell#populate, neither of which look like they should be causing this kind of behavior.