I was getting this all the time, it would rarely stop, also had a problem with the electric brake not releasing. Had it looked at and they couldn't find a problem. Eventually one time I got a engine warning light and when I took it elsewhere to be checked there was a lot wrong and they had to replace a few parts including the clutch sensor which was causing the brake and stop/start problems. This is a known problem with the car so it might be worth getting it checked as I had to leave it with them for 4 days as other things had gone wrong with the engine over the 6 months or so I had the problems.