I’m worried that my file has become corrupted. Here is what is happening.
I have a head with a head bone, and a set of bones controlling the mouth. I’m still in the process of distributing the weights between them, but this as come up.
Here are the weights for the head and upper left lip, respectively.
So the head bone has a weight of 1 over most of the head, but when I rotate it back, the front of the face and the lower back of the head don’t move. There are no other vertex weights for those vertices. Just the head bone.
In addition, if I move the upper lip left (Sorry, I’ve hit my picture per post limit) most of the front of the nose moves out with it, even though those vertices are only parented to the head bone. Even weirder, parts of the cheek move right as though they have negative weights.