build flagged as cc'd when its not

i spent and enormous amount of time making this multifunctional community lot and it keeps being flagged as modded when it is not. I build in a vanilla save so its literally impossible.  I removed all my custom art and went room by room.  Rooms I definitely know have next to nothing in them,  and are all part of the basic inventory are being deemed as modded. The build mod is acting wonky in itself.  It run super slow even with no mods,  and often greys out option to toggle between floors. Only solution is loading out of lot and loading back in which is an additional waste of time. Crashing has happened to which is really unusal when only building.