Definitely weight or a bug, GD can’t be that close to stalling angle, the low speed cue is AOA based so wrong gross weight would explain the picture, or simply a bug.
Regarding the definition of green dot speed, there is hardly any difference between all engine operating and engine out minimum drag speed (=GD) on a jet. This is more true for a turbojet than for a turbofan, still GD is a great approximation of minimum drag speed either all engines operating or engine-out and also is:
- Speed for best climb gradient.
- Speed for best endurance (holding).
- Speed for best glide range.
With increase in altitude, the best rate of climb speed reduces while the speed for best gradient remains constant (Vmd), at the aircraft theoretical ceiling: Vx = Vy = Vmd.