Revealing mistake: Certain monsters in Zord battles were designed for the first series. This is so Saban could use Japanese footage of ground fights, to save on shooting their own (As the costumes from series 1 carried over into series 2). Sometimes, you can see the Megazord, and Dragonzord, getting attacked (you may need to pause it). It should be the Thunderzord, or Tigerzord.
Revealing mistake: For shows like this, sped up footage can be used for effect on people or items to make them seem like they are going faster. However, in the Command Center after Alpha accident'y zaps himself, he starts to flail around the room rapidly with sped up camera. The rangers move out of the way at seemingly normal speed which would mean they were actually moving slowly when filming to make it appear they were normal. This is a good effect, except the sped up camera is given away by the fact the fluctuating lights on the golden poles around the room are flashing at much higher speeds by the sped up footage, giving it away. (00:05:12)
Revealing mistake: After the rope breaks and Bulk is on the floor, he and Skull look up as the ceiling dumps pieces onto them. After this, Bulk spits out white dust that's from the ceiling. However before this even happens as he starts to look up, you can see some white on his lips with his cheeks and mouth perched where he already has the powder in his mouth ready to spit out. (00:03:12)