supprisingly I found colored but by manufacturing status unpainted badyframes on ther way to the painter.
But: This happens not all the times when loading a savegame and it depends on the direction the bodyframe moves:
If you zoom out to the furthest 3 zoom levels where chassis are visible, a chassis that leaves the “fit body” station will have the wrong colour. My suspicion is that the colour reflects its green/red/yellow wait status. If that’s the case then it might be the desired behaviour, but if it was the desired behaviour, I’d expect all cars to change colours, not just those leaving “fit body”.
Screenshots attached of the zoom levels when the car changes from its expected silver colour, to green.