Usually that happens if you change the mouth pattern type in anim menu. So just ignore the whole facial expression there. Including eye pattern.
The thing you want should be done in HS2PE Adv > Blend Shape.
BTW this thing also can be used to make cumflation effect if you did it right.
Actually I never tinker with facial expression in all of my scenes. I could, but it's just a hassle. The stuff I said is based on an experiment I did in the past when I was thinking to make my scene looks nicer.
Also I just remembered there is a basic guide for VNGE.
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you go.
Go to /keyframe animations folder. There is a tutorial for blend shape.