Other mistake: The bishop that Dougal talks to about religion being pointless is supposed to be Irish but when he is telling Ted about his change of heart, the actor's English accent slips back in for a few seconds.
The Debt (2) - S3-E7
Other mistake: At the end when it shows that Xena did kill the "green dragon", you can see his eyes move when the camera pans around his face to show the hair clip in his temple.
The Secret of Management - S4-E9
Other mistake: The coffee mug that Cadbury gives Bill is empty.