Hmmm, sounds like a manufacturing defect. I guess you'd rather pick apart plot holes than sit back and enjoy the show. I suppose in some dark corner of the universe that can be considered fun. I will admit that I do like to spot continuity issues in TV and movies, but I try not to let it interfere with my viewing pleasure. Probably one of the easiest to spot is the magic glass that changes fluid levels constantly when the person it sits in front of never even takes a sip. That and articles of clothing that inexplicably move about the person for no reason. However, trying to apply logic to any TV show or movie is an exercise in futility and a complete waste of time. It's called poetic license. The writer will bend the laws of physics to obtain the desired cinematic effect no matter how ridiculous it may seem. If it bothers you then I would suggest either changing the channel or finding something else to occupy your time.