Are you sure it's the motor? If so, is it signaling an error? (Not reading status back is in general a bad habit, because it makes debugging harder.)...
If the servo cannot get to the desired goal, it will generate an error to tell you this. The practice of "set a goal position that is not achievable"...
Not really. The main question is if you have command response turned on; if so, you may have to wait for a timeout if the servo didn't get the packet...
Synopsis:
Twitch is a 3 servo hexapod (for lack of better classification). Twitch is controlled via two Wixel boards and an Arbotix Commander. The mobility of Twitch far greater than any other approach to a 3-servo walker that I have seen, and makes for a cheap bot that I can let anyone try driving.