The "50% position" for reaction wheels is stationary. They then accelerate in one direction or the other, depending on need. If the flying platform had a naturally stable hovering position, then the reaction wheels would not be rotating at all.
The setup used obviously had some inherent stability issues which were too extreme for the control system to deal with. Perhaps tweaking might home in on some better results, but from what I saw, it was a long way from critical damping.