My car does the same thing. I really don't think you have anything to worry about since my car only has 7650 miles on it. It does it for a few seconds upon startup and quickly disappears. I believe what has been said here is true as I don't start my car for weeks at a time so there is no oil up top.
Don't worry about it, enjoy the car!
Mark
Don't worry about it, enjoy the car!
Mark