Has happened a few times over the years on our five BMWs. Usually just reposition the hose in the tank neck slightly to 'fix' it. I've never really figured out what causes it to trip early. It always seems to work eventually though.
“Character is doing the right thing when nobody’s looking. There are too many people who think that the only thing that’s right is to get by, and the only thing that’s wrong is to get caught.”
- J.C. Watts Jr.