Deliberate mistake: Monkey Bulk & Skull are driving Lt. Stone's car. From inside shots of the car, Monkey Bulk's head doesn't go above the headrest. From outside shots, we can see the guy who was driving the car - his head is way above the headrest, and he's wearing a frizzy fur costume (Monkey Bulk & Skull's fur is very fine).
Deliberate mistake: A few deliberate mistakes here. It was around this time that 3 of the actors on the show (Austin St. John, Walter Jones, and Thuy Trang; who played Jason, Zack, and Trini) walked out over pay issues. So, to work around this until replacement rangers could be found, Saban used old footage of the 3 that walked out. The mistakes are as follows: 1) Tommy is shown to be wearing green. The Rangers wore clothes that matched the colour of their powers - Tommy was now the White Ranger (and should be wearing White clothing), as the Green Ranger powers had been destroyed. 2) Zack's hair changed from dreads, to his flat cut. This had an instant effect on Kimberley and Tommy's hair (again, due to the old footage), which had gotten noticeably longer as the series progressed. 3) Jason, Zack, and Trini's voices were different when they were morphed - obviously, they were voice sound-a-likes.