It could be Model view options or Graphic Overrides.
To troubleshoot, if you have a view where they do show, try temporarily switching the Model View Options to one you know works? That will rule out MVOs.
If you switch the Graphic Overrides to no overrides, that would rule out GOs.
GRAPHISOFT CERTIFIED ARCHICAD BIM MANAGER
ARCHICAD 18-26 | BIMcloud Basic | CI Tools | Grasshopper - Rhino | CloudCompare