I'm going to walk out into a limb here.
I think this a big advantage of using a hydraulic left-right interconnect instead of a mechanical anti-roll setup.
Under certain load parameters, it can be tuned stiff, as would be desirable in medium to high-speed corners.
However, things like the kerb in the video are sudden hits which have the potential to lift the car right off the ground if it's too stiff laterally. Judging by the video, this car has what amounts to a blow off valve for its hydraulic interconnect.
I know when front-rear interconnect was barred, there was some debate about the merits of hydraulic interconnect left-right. The Merc has been said to ride the kerbs quite nicely and I think this is why. This video makes the rear wheels appear entirely independent in their movements, it would look absurd around the rest of the circuit if something fancy wasn't happening IMO.