First of all, here is my log, if you need it: http://tinyurl.com/kmd9pe3

 

So, I was using a seed that my friend gave me, and went to a location where there was supposed to be a skeleton spawner, but it was a spider spawner. I then made a new world with the seed in a vanilla 1.7.10 world, and saw that it was, in fact, a skeleton spawner without Forge.

 

I then put just Forge on that vanilla 1.7.10, and made a new world with that seed again. It was a spider spawner. So, I figured it must be Forge causing this.

 

(To clarify, Forge is not changing a spawner that's already been loaded, its that it generates the spawner different from what it's supposed to be).

 

Here is a picture of the spawner without Forge:

 

and with Forge:

 

Here is the seed if you want to see it for yourself: 2138374464889032671

 

it is doing that for me to

World gen like this is extremely temperamental.

I'll look into it, but no guarantees, things must poll the random numbers the EXACT right number of times in order for the spawner to be the same.

Stuck on my to-do very low level.

Thanks. Obviously, its not a huge deal, I just thought I'd let you know.