That sounds like a wheel sensor or something that aids the stability control system. Its tuff when you have an intermittent issue like that. You will need to take it back to the shop and if they can get the problem to occur, then they should be able to fix it for you.
Its tuff when there is no cel and the problem does not occur while the shop has the car. If its happening often enough for them to duplicate it, then they should be able to repair it.
Does it happen if you turn DTC completely off ?