If your renovation settings for New Construction have an override for existing elements, it will display the existing elements as modified by the demolished elements. Thus, if you demo a door, and have an override on the display of existing elements, the door opening will show. If you turn off any override of existing elements (set to "Show"), then the opening will not show. That is essentially what happens when you change to "Project Completion" status.
ArchiCAD 22
Win 10