Ghost parts are not visible when overlaying a ghost cube

Question

I'm trying to create objects using an overlay manager. https://aps.autodesk.com/en/docs/viewer/v7/reference/Viewing/OverlayManager/

I prepared a ghost cube that contains an overlay, but the ghost parts that overlap the overlay are not displayed.

I tried enabling depthWrite and depthTest for the material used for the overlay, and changing the renderOrder of the mesh, but it had no effect.

Is it because of the specifications that overlapping ghost members cannot be expressed?

Thanks for the help.