Why a helicopter falling during auto-rotation could reach a terminal speed?

During auto-rotation, a helicopter's main rotor generates lift from the relative wind passing over the blades as the helicopter descends. If the helicopter dives too steeply during auto-rotation, the increased airspeed can cause the rotor blades to stall, reducing lift and potentially allowing the helicopter to reach terminal velocity. At terminal velocity, the forces of gravity and air resistance are balanced, leading to a constant descent speed.