Yafaray Switching Materials around

After working on a scene for quite a while, yafaray has begun to switch the materials of various objects. Sometimes it switches the whole material, sometimes it will just take one layer (eg specular, diffuse). I have no idea what would cause this or how to fix it. I tried re-making all my materials, but this only served to switch them in new and exciting ways.

Need help ASAP, this was supposed to be finished this week