Sorry for the late reply - I’ve been real busy
In regard to Maya asking you to save even after a manual save is a mystery to me also.
The scene was used for several renders with a design I was trying to setup. The strange Maya behavior doesn’t happen with that project file - only with the hurriedly clean-out version I 1st sent you.
To fix the 'faulty' scene, I simply selected the floor, back wall, both lights & the 3 nurb shapes - then exported selection. The newly created Maya file seemed to behave itself.
I know this doesn’t really answer your question, just letting you know what happened…
PS: Any more progress with the model??