Landing bounce most probably caused by PIO
When I saw the bounce video I immediately thought they were in direct law. This is now confirmed by the Russian interviews with the Pilot. The SSJ FBW is very good according to pilots I've spoken with. It's flight laws gives you a responsive but well-damped aircraft to fly. The computers regulate the stick to movables gearing and damping dependent on the flight situation. This is all gone in Direct law. You are flying an aircraft which is now responding directly 1:1 to stick and pedal movements, no gearing, no damping, no corrections.
This surprises the pilot on short final when he shall start the flare IMO as he could only have flown Direct Law in simulator training and then not much. He is most likely in PIO (Pilot Induced Oscillation) from short final, overcorrecting through the flare and then further on. It's difficult to stop a PIO once it has started. When you feel you don't have the aircraft responding as you want your muscles stiffen up as adrenalin pumps and this increases the PIO probability. The way to stop PIO is to let go of the stick for a second and come back with a softer arm but this is not what the Pilot can or dare to do in his situation. I guess the Direct Law fulfills the certification requirements as these are relaxed for an emergency backup mode. But one shall perhaps re-evaluate it's gearing.