Huh, yeah you're right. But that is really weird because I didn't change anything about the armature or weights at all during my tests. But you're right, the neck bone doesn't have any vertex group assigned. o.O
Your Fix uhmmm. The neck looks to be aligned in the right direction now but it's suddenly a lot smaller. And something weird influences the arms all of the sudden. xD
View attachment 139096
View attachment 139097
Let's see if I can fix this now that I know what the issue is.
Edit- Oh what the heck. The neck is now influenced by customization sliders, and not the head. I thought that was never the case before...
Edit2- Thanks to our lord and savior UndercoverPervert, I can now extract DAE from a pac with fixed bones which doesn't mess up missing weights and stuff. So I could fix my modified body by transferring the weights over from a new fixed default body.
View attachment 139113
Looks good now. In case anyone wants, I'll attach this body as well.