I suspect thats the problem with my wife's 06, started getting a CEL a few months ago that would go away after a couple days of driving, always came on after she filled it up but didn't come one everytime she filled up.
On my M3's that I had a few years ago it was not unusual for this to happen and you just got a new gas cap.
On my M3's that I had a few years ago it was not unusual for this to happen and you just got a new gas cap.