In head lock mode, the neck can sometimes default to bending at a strange angle. As you can see by how the choker looks in these screenshots, in the first image its bent back in head lock mode. The second is the default position in t-pose mode.

I believe this happens when the neck isn't straight in the rig. I tried straightening out the neck in blender (image 3 pre-straighten, image 4 post-straighten, top bone is head, middle is neck, bottom is chest) and it appeared to resolve the issue, but I assume not all avatars with this potential problem can easily be fixed simply because the author doesn't have the know how nor uploaded it.