I was trying to add a nutcracker jaw to a robot character I am building from scratch and the puppet just gets all whacky when I add it. For some reason it tends to "twist" the head its in, even though it is set to independent. I can post the puppet if that would help. Is it OK to post it to the forums?
You can certainly share your puppet here for others to diagnose. Upload to google drive or simailar and share a link here. Don't try sharing the puppet directly here - i think there might be size limits or something. Google drive is more reliable.
What can help with diagnosis is turning on the yellow mesh of triangles in the scene window. You can then see the meshes move ar'ound - sometimes you notice things are connected that you did not expect, or find a spot on the layer that is not moving when everything else is, causing distortion.