To reproduce:
1. Open attached project
2. Open scene sc1
3. Select all gameobjects except "body" and attach them as children to "body"

Weird part: if you attach children (to a non scaled parent) and then scale the parent this will give you different results than attaching to a pre-scaled parent

Explanation: This is a flaw in how the scaling and parenting works in unity. This can not be fixed without breaking all content out there. We have taken note of it.