Dungeon Spawner contains a different mob in 14w04b than in previous versions when regenerated

Is this only if you re-create the world in 14w04b or will it replace an already existing spawner after updating?

Ryan it does not replace spawners that have already spawned as far as I have tested.

Using Seed: 725727103968107578

You spawn right next to a village, on the other side of the village is a desert with a surface dungeon. Creating the world in 1.7.4 it is a skeleton spawner. Switching to the snapshot and loading the world, it remains skeleton. If you regen the world with snapshot it switches to a zombie spawner. I've only seen Zombie spawners created with the snapshot, but my sample size is too low to conclude that they're ALL zombies for certain.

This also happened to me, the spider spawner was replaced by a zombie spawner.

From the title I thought this meant "my spawners changed type" but it only applies to newly generated stuff vs old generated stuff, so I changed that.

Minor things like this can change between versions. Not going to fix, sorry.

I found a skeleton spawner (that was previously zombie) with seed -1278695978 at coordinates -102, 36, 2880, so it looks like there are also skeleton and spider spawners, they aren't all zombie spawners.

Zombie: 50%
Skeleton, Spider: 25% each
(that applies only if they didn't change it in the snapshots)

I'm quite sure it's 25% for zombie and spider and 50% for skeleton, all the ones I find are usually skeleton.