The Catwoman from Channel Six - S2-E12
Plot hole: April is transformed into a Catwoman by a teleportation accident. Shredder puts a mind control collar on her, and she attacks the turtles. The turtles manage to remove the collar, and the fight ends. Shortly afterwards, April returns to her normal form, without any explanation.
Invasion of the Punk Frogs - S2-E8
Plot hole: Shredder meets the frogs for the first time and gives them clothes using the holographic projector. The frogs continue to wear the same clothes for the rest of the episode, even without Shredder being around.
Continuity mistake: The turtle van falls on a bridge, the turtles escape swimming. Shortly afterwards, April appears driving the van, looking for the turtles.
Chosen answer: No, that's just the kind of mistake that gets made when you contract a foreign company completely unfamiliar with the product in question to produce your marketing materials as cheaply as possibly.
Phixius ★