Lens "colour rendition"

Lens colour rendition seems a globally accepted phenomenon. Is there any text book type material that explains the physics behind this or is it magic?

All modern lenses, if not put on a camera body and held in front of a colour neutral material such as white paper and looked through, should look colour neutral (the paper around the lens and through the lens should be the same colour to the naked eye). So colour rendition does not seem a cast/filter effect.

Are there controlled tests where different lenses are used on the same camera, with manual setting of the same exposure, same WB, same software contrast, same ISO, etc. and consistently different colour behaviours? If so what would be the optical design reason for this?

I've had radically different colour behaviour from different lenses but these seem to have been caused by the camera setting a different something (WB, for e.g.) automatically when those lenses were used.