I believe, and please correct me if I’m wrong. It appears the third cup holder is visible in several images in the online gallery at this site. It’s always shown in the closed position and is only visible from the passenger side view of the center console just below and forward of the gear shift. It looks like a thin rectangular shape, the type of cup holder that you would push in to initiate the spring release. This would be a more convenient location to reach than between the seats.