Mesh Twists during posing with rigify rig

Does anyone know of a possible cause of twisting of the mesh during posing?
The weight paint is as shown, the bone is the Head DEF bone.
There are two modifiers on the mesh, Subsurf and Armature.
(makes no difference if subsurf is applied)



check in wheight-paint-mode the other bones,
i am quite shure you then will find another bone
with some part of the head showing red-green … colored influence.

most times… it would be one of the body bones …

test-dr, bingo, you’re right, never occurred to me. Thanks, we’re moving again! Why the shoulder should weight the upper part of the head in the automatic weighting…

Automatic weighting is far from perfect. Particularly around the head area. I don’t know why it would have a weight from a body bone but stranger things have happened.