I don't know if the Alt button is the hotkey for stop, so that might be your problem. You could always do it the old fashioned way and hit the stop button on the interface. Clicking multiple times is a habit of mine, something that I would suggest (you need to make sure the order gets through damnit!)


If that isn't the problem, are you refering to "still constantly firing" or "fires one volley and then stops"? Even if you hit the stop button, the archers tend to finish through with a volley, so you can't stop it completely, just stop it from happening again.