So far the two structures I've come across in world gen have generated with Pig Spawners instead of whatever spawner might have been intended for the structure.

This is one of them,

This is the other one.

I loaded up a fresh world and started looking for these structures to see for myself.

I found the first structure, but it's completely fine, it contains a Zombie Spawner, not a Pig Spawner.

Seed: 8382539351900587069
Location: X = 279, Y = 66, Z = -375

Can you confirm that it still spawns a Pig Spawner for you?

Or alternatively, if you've been playing on the server, then tell me the coordiantes (and the seed, although I can figure that out myself).

Sorry it took me so long to respond to this, I've been having the same issues a lot of people have been having with going from multiplayer to singleplayer, and it just skipped my mind. Ill do the Singleplayer question first, so to avoid the galacticraft errors.

Loading up the world in single player and moving to the structure, it actually spawns a Witch Spawner, but I think that is actually intended, for it to be any random variant of dangerous mob. I decided to fly around for a bit, I found 5 more copies of the spruce hut structure and they all had violent mob spawners as well, and I found another copy of the crypt structure and it also had a zombie spawner in it

Next was giving the cords of the structures I'd found in the beta server that were supposed to have violent mobs but didn't. I flew around and found a few more, too, and they all had pig spawners of some kind. I have no idea what the seed for the server world is, sorry. XD
[x:-2533, y:68, z:-4080]
[x:-2844, y:70, z:-4599]
[x:-2902, y:63, z:-4728]
[x:-2879, y:62, z:-4713]
[x:-2767, y:70, z:-4521]

Just a thought, but perhaps it has something to do with the way the chunks were pregenned on the server? To the best of my knowledge, overworld was completely pre-generated inside the world borders on the beta test server, so it's just a weird guess.

There's also one of these structures at x -1005 z -2041 near my area with a pig spawner in it on the beta test server.

I also found a regular Zombie spawner in one of these structures on the Beta server. Coords: X = 146, Y = 68, Z = -183. So it's not like all of them are Pig Spawners.
So, still have no clue what could be causing this.

As nobody has created an issue remarking on this, and it appears to be resolved, this is being closed. Please reopen if any more evidence is found.