the EXPEDITE button is a horrible thing!
It will very sharply pitch up the airplane to achieve green dot, often overshooting it. Ugly! And like I said, that green dot can be good at the current level, but it is below high level green dot. Also, there might be no need at all of such a radical speed reduction.
If you want to go to green dot, do it with selected speed, nicely and progressively. EXPEDITE does no magic, it is a very silly option, and on top of that, the button is in the same place where the 340s have the ALT HOLD button, so imagine what happens in airlines with both types.