The 350/355 should be flown with some cyclic friction on, even to the point where you get tired of pushing it around which is a solution for "stick stirrers", and should have a minimum friction which gets overlooked, if the cyclic falls over when you let it go you have some serious issues that should be addressed. Pretty sure this even mentioned in the RFM. The rotor has a pretty big hinge offset and has high control power and is not decoupled for movement between the frame and the dynamics and you will start up a resonance that people fight with. Don't move the cyclic and the aircraft will sit there all day on it's own. M/R balance can also have an effect on the coupling, I have had a 355 with extremely good balance that would hover on it's own without cyclic input for up to 45 seconds. The location of the TR relative to the main rotor is influenced by the wake propagation from the MR which probably misses the TR OGE and influences it IGE as the wake changes from convergence to divergence with interesting part being the transition between the two as for a fixed TR pitch the thrust will change when fed from the wake which ends up with yaw and secondary roll about the vertical C of M. (The vertical distance from the TR to the rotor head is a myth) So to account for that you just need to keep the desired heading. Address these points and these aircraft are easy to fly and land smoothly.
In the video this is just dynamic pitch over i.e. rollover in a different plane. Panic when the aircraft pitches back with FWD cyclic which has way more travel than AFT from neutral and with inertia the C of M gets FWD of the ground contact point and you have less AFT than FWD travel it isn't coming back and all bets are off because physics always prevails.