This is a real pain when it occurs. As I understand it, this is the effect of pose makers selecting "include morphs?" when saving the pose. If you download a set of poses, there is absolutely no way of telling whether they are going to reset your character's face or not, short of hacking inside the .pz2 file with a text editor. Not good. You can easily lose that lovely face that you spent so long making. Usually the effect is to blank all the facial features to zero, rather than giving the character a different (non-zero) face. The best defence is as follows, for a character you are going to re-use. Once you have finished the face, and with all expressions set to zero, do spawn morph target on the head. Call the result "Freda" or whatever the character name is. You now have a Freda morph which is set to zero. Set all the face morphs to zero. Now set Freda to 1.0. You now have a protected character face.