Is the back spine a child of the root?
I think it should have a composition similar to the bone above it (spine2?), so you might compare those.
yess , it is .. im new to this , wht u mean by composition ? sorry
Sorry, might not have been the best word choice 😅
I mean, for example if the bone above the back spine is moving, the back spine should move as well if you give it similar settings (hierarchy, point/orient constraints, etc.)
Can you post a picture of the outliner where the back spine appears?
How is your cluster4Handle being controlled? What does it have inside?