[Alan Anderson]

What kind of speed controller are you using? I occasionally saw the original Talons "twitch" when something induced noise on the PWM cable.

I have also seen very brief twitches occur using RoboRIO firmware from several years ago when the robot code lost communication for a moment and disabled the PWM outputs at just the right/wrong time to make the speed controller think it had gotten a single "run backwards at high speed" pulse before timing out and shutting off. I thought that undesired behavior was fixed, though.