Bangs morph with shoulder slider unwanted - how to fix?

Hi. I'll explain how to find the cause of the problem so that you know:
When the mesh does not behave right when you adjust the body parameters or facial features, it's the problem with morphing

There are 3 things responsible for morphing:
1). Bones with "CAS" in their names. This one is the first thing you check because it is rarely the cause. Soon you will memorize in what areas those bones are (breast, face) present, so you may not need to check that at all.
So how to check:
- in edit mode select one vertex in the area where the issue happens. To the right you'll see the list of bones that affect the vertex;
- if you will see nothing that has "CAS" (for example, b__CAS_JawComp__) in the name, then its not it
While we are on the subject of weights, when you will select that vertex, you'll see a lot of vertex groups with 0.000 values. They should not be there and s4s will remove them. However, it can remove them in a way that is not ideal, so it is best to do it yourself in Blender. When you transfer weights, always Clean them and Limit total.
2). Vertex paint. The hair is painted with 007F3F along the hairline(to morph with the Detail mode sliders), 007f02 from the root to where jawbones start(to move with the head slider), the rest is painted with 007f00 (to NOT move with some sliders). I always advice people to start by cloning a similarly shaped maxis item and studying it. This is something you'd need to study by sampling colors along the length.
Anyway, it the area is painted with the color it should be painted, in your case 007f00, it is not the cause of the problem
3). And finally, uv_1. 90% of the time this is the cause but i advice you to save it for the end because the other two things must be right for uv_1 to work right.
So in this situation you need to sort of use logic. So you transferred the uvs from the torso+head for the tails to move with the back, right? But where else does the hair reach the torso? In the bangs area. Do you need them to morph with the shoulders? Obviously not, so the logical thing it to move their uvs away from the shoulders. Try doing it like in the pic: select this area, W - Weld, move it up, do on the other side