I've noticed this too, I play with pressing the light but if the light is on in the button I believe it is deactivated. It resets when I restart my car. I believe the orange/yellow A indicates that it is not shutting down, when it is Green that is when it turns off. But why it lights up on the Dash as orange yellow A when it is deactivated I'm not sure the reason.
In Eco mode It shuts off which is fine when I'm at the light I lightly tap the accelerator and the engine pops back if auto hold is on, if not just lightly release the brake peddle a little and it pops on there too, so I've learned when the light is about to turn green to do this so I'm not having to wait an extra second.
However what is annoying is when I pull into my garage and stop the engine shuts off, and then I go to move the car into Park, and the engine pops back on which is silly to me since I'm actually ready to turn the car off. It should stay off while in park and then I can just turn off the car like normal without having to have the engine restart and shut down again. Kind of a minor complaint but it seems like it doesn't make sense when shifting to Park for it to pop back on.