Revealing mistake: Throughout numerous episodes while the team is supposed to be driving the van, the gear selector can be seen in the "park" position.
Revealing mistake: When the Gadget Coat is punctured by a bird and it pops, all that is left of Gadget are his head and hands floating in mid-air for a couple of frames.
Other mistake: When Teela is at Snake Mountain, she overhears TrapJaw saying how Skeletor's electrical creature will control all of the machines at the palace. When Teela returns to He-Man, she says that the creature Skeletor created is called Byte. There's no way for Teela to know the name of the creature, since TrapJaw never referred to it by name. (00:14:24 - 00:15:20)