I get this on occasion, it seems to occur after loading in certain clothing models.  I can't remember what ihad loaded, but basically afterwards certain aspects of V4 didn't work.  Not just morphs but I was unable to turn, bend etc. the neck or head.

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I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use.
-Galileo