Preliminary data based on the notification from the Norwegian authorities:
First limit indicator failure early in the flight, followed by a reset on VEMD. Much later in the flight, Red Gov light warning and NR speed sharp increase while the helicopter gains uncommanded altitude.
Pilot drops sling load, sets engine control to manual, engine spools down rapidly and stabilizes afterwards.
The helicopter is still gaining altitude and sets a heavy nose down angle and heads toward a safe landing spot, as well as a high bank angle.
Flares heavily and lands lightly. The engine seemed to have a low RPM when touched down.