The dub music is NOT a mistake.
It was definitely a mistake, my good pal.
It was around the time when most TV anime dubs would replace most to all of the BGM in order to make the series marketable. Nowadays, the practice of replacing BGM is unacceptable by today's anime standards.
Bruce Faulconer's Music was never meant to be a part of the Dragon Ball series. It just doesn't fit the genre on what Dragon Ball is about.