Just Cause 2 Missile Glitch

My guess is that the missile is trying to home in on something that's located within the circle of its path? And it can't turn in acutely enough, as it were, so it constantly goes around it. It would be like trying to deliberately crash into a telegraph pole that you're parked beside; you lock the steering wheel but the pole remains constantly on your left (or right). Of course you can manage to collide with the pole by driving away from the pole, turning around and taking a proper run at it... but the missile doesn't know that! ;)