Just another update, we will not be updating to that build of Bukkit, as it does not fix anything xD. The 'fix' fixed nothing. From Amaranth his self. First the commit was bad, and did not compile, then Amaranth fixed that, then it did not fix anything. But the issue has been acknowledged and is being worked on.
You must be listening to a different bukkit team, because I was on #bukkitdev all night, and the 'fix' looked like it was going to work, but did not. also http://empireminecraft.com/threads/1-4-current-bugs.17286/
I was looking on leaky.bukkit https://bukkit.atlassian.net/browse/BUKKIT-2760#comment-20276 Travis has confirmed it's fixed quite a few times.
Yeah, the same guy that has posted that it was nothing that could be fixed only two posts before that. The fact of the matter is, he fixed it for him, but every other server running CraftBukkit, it did not fix.
Nope, we have a test up and running on stage, it will be pushed later tonight to all servers, and yes, they spawn in ALL fortresses, be prepared... the nether is dangerous again. Also, watch out if you have a blaze spawner, they apparently are prime spawning areas for wither skelies and rogue blazes