Moving child transform also moves parent rigidbody

In this situation we have the parent gameobject which posses the rigidbody and is basically an empty gameobject otherwise

then we have the child which is suppose to be a spinning top my script rotates the child at a specify speed around the transforms rotation

now i can lock the rigidbody rotations thats not an issue.

the movement is controlled by adding force to the rigidbody and rotating the transforms rotation

however the spinning transform rotation from the child is somehow moving the transform position of the rigidbody which is attached to the parent object.

i need to be able to use the magnitude from the parents for a damage calculation when the spinning tops hit each other.

But because the child spinning top model is being rotated via transform rotation and somehow moving the parent rigidbodys transform. when the object is sitting idle the magnitude randomly jumps around,

when i disable the child spinning portion the magnitude acts normally.

how can i have a child object spin via transform rotation and have it not move the parented objects rigidbody?