So..in a nutshell, shadows aren't showing up in walls that are left in an "existing" state, yet once a new window, door, opening, removed window in a demo state is created....then the shadows on the walls in their existing states....show shadows...........what's happening here?
...Bobby Hollywood live from... i>u Edgewater, FL! SOFTWARE VERSION: Archicad 22, Archicad 23 Windows7 -OS, MAC Maverick OS
Assuming I have understood what you are trying to do correctly I think the issue is that you need to tell the Renovation Filters for the Existing Graphic Override NOT to override drafting fills. See attached screenshots.
Lee Hankins ArchiCAD 4.5 - ARCHICAD 26UKI Intel 3010 and Apple Silicon macOS Monterey (12.5)