Sins of the Fathers Chapter 3: Attack of the Octobot - S3-E3
Continuity mistake: When Doc Ock is being taken away in handcuffs at the end of the episode, his mechanical arms are missing. The arms were fused to his spine, so the police couldn't have confiscated them.
The Origin of the Fantastic Four: Part 2 - S1-E2
Deliberate mistake: When the Thing is doused with the chemical that reverts him back to human form, he somehow also is suddenly wearing a T-shirt, jeans with a belt, and shoes, which is illogical since the Thing wears a speedo with no shirt and is barefoot. (00:05:35)