From the looks of it some how there is weight on the points between the brows and the mouth shape.... Did you smooth the character before or after making the blendshapes?


Its hard to explain a bit.. when I do blendshapes i make all the shapes in there lowest form then i only smooth the main head after all the shapes are done... I found if i dont do it that why i do get some moving around in places i dont wont kinda like your mouth.

You can also try combineing the sliders a bit more to get the shap backand key it once you have back to normal