I suspect it's something like this:
Maybe there is a parallel shaft connecting the upper rocker to a secondary rocker which is submerged near the bottom. When the main rocker pivots, the secondary one pivots. Same phase motions of the left and right wheels (pure heave) may cause lengthening or compression of the device at the bottom. Opposite phase motions would just cause the entire device to translate from left to right with with no effect to the independent corner stiffness and damping. That's my guess! Looks insane.
I still can't workout what the anti-roll bar is supposed to be connected to.