An Affair to Dismember - S1-E8
Deliberate mistake: Right after the credits, we see an establishing shot of the mayor's house but it's a reused shot from episode four from when Jake and Lexy snuck inside, just without the digitally added smoke. What gives it away? The fact you can see Jake and Lexy at the bottom corner sneaking in, wearing the clothes they wore in episode four, even though they're already inside and wearing different clothes.
Just Let Go - S1-E4
Deliberate mistake: When Devon does an internet search for Chucky, pictures of Tiffany and Nica pop up. But they're still-shots from "Bride of Chucky" and "Cult of Chucky." It makes no sense that they'd be in an internet search - nobody could have taken those photos.
Answer: They were blamed for the death of Jake's foster brother, which was deemed a terrible accident, and they were sent to the reform school as a punishment. Presumably, when they had to leave the reform school given what happened, they were instead given community service as punishment.
TedStixon