That's strange because my car was built 4/08 and i have this exact problem.
I took it in one time (along with maintenance and some other things to get done) and the next morning i had the same problem. Another person on this forum replaced theirs 3+ times and it still had the same problem; He was complaining that his wife had a hard time starting the car (or something along those lines).
I've gotten used to it, but next time i'm at the dealership, i'll get it replaced and it'll probably still lose pressure
