Did you subdivide her because that can happen for a few reasons with meshes not optimized for Pixar SubD. Things that can sometimes trigger it: Bad welds. NGons (polygons with more than 4 sides). Vertices that overlap - especially if it's near the 0 line of the x axis, stray verts. Only one of these things can be corrected without destroying the vertex order and that's the one where vertices overlap. Fixing any of the other issues will result in a new vertex order/count and will break your morphs. 

 

So yeah.