Roof in Revit and IFCBuildingElementPart- IFC4

I am testing IFC4 export from Revit. I chose in Revit: Parts Visibility: Show parts, in order to obtain IFCBuildingElementPart. (photo 1 from Revit2024)

Whereas the problem is for the Roof, I can’t split the element into parts (photo 2 from BIMCollabZoom, Photo 3 the IFC text)
The Question: why we can obtain Building Element Part, so that IFCBuildingElementPart for all elements (Wall, Ceiling, Floor) and not for the Roof.
Is it a bug ? or I missed something.

Thank you in advance

Probably just because you haven’t split the roof into parts. If you send this as an email to me I can get you more support on it - angel . velez @ autodesk . com.