Thanks guys, I have a much better idea of what happened now.
Interestingly enough (for me anyway, maybe not for anyone else here), I've experienced unequal hydraulic assist before, although with a tractor. Massey Furgeson 235 with ram assist power steering (a unidirectional ram on each side). On this particular tractor, one of the rams was blown out and didn't work at all. It's fun enough trying to steer a slow moving vehicle that wants to be easy to control in one direction, I can't imagine doing that with a helicopter. I guess the video demonstrates what happens when you try?
Side note: there was an Astar flying around today with a sling load that looked a whole lot like a big rocket (longer than the helicopter). Slung so it was horizontal (like it was flying under the helicopter). It kept on flying down the runway at Fairbanks, although I don't know if that's all it did today. Someone told me they heard it was some fancy ground penetrating radar gadget for oil exploration.