Thanks, What I find strange is that in the first image the green dot keeps going up, even at a very high speed.
Again, I might be wrong but my guess is that it's actually normal for Airbus logic, even though it looks strange.
The green dot speed isn’t linked to how fast you’re currently going but it’s more of a reference speed, calculated from the weight (heavier aircraft means higher green dot speed), altitude (higher altitude means thinner air and therefore higher true airspeed for same lift)...
So even if you’re already going fast, the green dot will keep climbing with altitude because the air density is dropping. To maintain the same lift-to-drag ratio and climb performance, you need a higher indicated speed so the “green dot” creeps upward on the tape as you climb.
That’s why in the screenshot it’s still rising, even though you’re already near Mach 0.9... it’s not “chasing” your current speed, it’s just showing where that best lift/drag point is for your current weight and altitude.