SceneGraphObjects aquiring parents without add

Has anyone else encountered a situation where upon adding a newly constructed SceneGraphObject you get the “Multiple parent exception”?
First ran into this when constructing an array of Shape3Ds in a class designed to handle the data for a single model. When I used a ‘for’ loop to iteratively add the shape3ds to a transform group I got the error on the first addChild. The parent (using getParent()) was a TranformGroup. I solved this by having my model class only supply the GeometryArray and Appearance and building the shape3ds in the ‘for’ loop at attachment.
Now I am encountering the same problem with Backgrounds, with no convienent work-around.
Jim