@pen11: That's not the problem. I've completed the level multiple times, and "saved" my score every time, and hit the "refresh" button almost as many times. This level simply won't register my score and come off of the "Best levels..." list.
right after you complete it go to the best levels you haven't scored on and hit the little red thing in the corner. it is the refresh button and it should be gone after that.
@gundu1: I'm having the same problem. For some reason this level isn't registering my score and/or coming off of my "Best levels you haven't scored on" list. Is anyone else encountering this?