i imagine you are all right at this moment. a lot of times when a stop lamp switch starts to show an intermittently implausible signal, you will get that warning which will go away when the ignition is cycled. there is also a DTB for your car about a wiring update for the esp control unit due to corrosion on the connectors. if the light is not on there isn't a problem, but i would mention to your service advisor at your next scheduled maintenance that the esp warning appears intermittently.