Continuity mistake: "The Time of the Wolf": Robin slays his evil twin and leaves him on the grass near the standing stones. The body then changes positions without anyone touching it. When Robin leaves, its head is pointing to screen-right. But when Marion arrives, Evil Robin has done an about-face: his corpse is now pointing to the left. (01:21:00)
The Return of Optimus Prime (1) - S3-E29
Continuity mistake: At the end of the episode 'Dark Awakening', Optimus is seen without an eye and an arm, he also has other damaged points, but at the beginning of this episode, when Jessica and Gregory get to Optimus, he is in perfect condition with no damage.
Another Song for Christmas - S1-E13
Continuity mistake: After Honest Eddy swaps cars with the old couple, there is a shot with him in the car. There is no smoke coming out of the back. Change angles, and smoke is coming out again.