FYI, apparently there was nothing wrong with my process, somehow the geometry was just getting corrupted in Workbench so I tore it down, started over, same process in Spaceclaim, and now it's working. HOWEVER... if you've done what I'm describing in the past and are confused, as I was, by how thing show up in the Mechanical model tree, just know that Mechanical will treat combined bodies with shared topology from Spaceclaim appropriately, but, it will NOT show up like it used to in previous ANSYS releases as a "combined" part in the Mechanical model tree; they now look like separate parts there for some reason. I much prefered the previous release's handling of Spaceclaim geometry so that it was obvious in Mechanical, what was going to behave as a combined component.
You are navigating away from the AIS Discovery experience