Indeed a sample would help.
I was thinking that extracting faces from the Geometry Property of an Element is an option. This way, the step of selecting through UI can be avoided, and peculiar issues related to UI selection might be skipped then. And I am using Revit 2025 and there’s a neat little one called Element.GetGeometry, though I am not sure if it is available in earlier builds. Once you hook the node to the ones you cant select, see if there are faces. It gets interesting if there are no faces in the output.
Some useful links (get geometry through code which I think it is what the node does)
API usage of “get_Geometry” command to retrieve element geometry - Developers - Dynamo