Other mistake: When the Simpsons' drives the electaurus off the edge of the harbour, it is shown that the front of the car goes downwards. When it cuts to the interior view with the Simpsons' screaming, the view from the back window is tilting down, suggesting the rear is going down and the front coming up. But in the next shot the car is seen in the water with the front down.
Other mistake: In "Desperately Xeeking Xena", at one point she approaches the Collector, who is about to get a light saber. We can see the back of the pouch that Xena is in, but the tape on the other side isn't visible, even though it is a transparent pouch.