Crimes and Meg's Demeanor - S16-E8
Continuity mistake: At the beginning of this episode Peter is talking to Meg about her senior year in high school. This makes no sense considering she turned 18 in season 10, which was released in 2012.
And Then There Were Fewer - S9-E1
Continuity mistake: When Muriel is killed in the flashback, she is on the floor with her arms open and head down. When they find her, her head is tilted and her arms are straight to her body.
Continuity mistake: When Cleveland and Peter are in his car making sandwiches, Peter originally makes one sandwich that he splits with Cleveland. When the two men approach the car, saying they smelled something good, they offer $10 a piece for a sandwich. Peter then hands them each a sandwich that he couldn't have made that quickly.
Continuity mistake: Meg comes in the kitchen and Peter pulls out her chair for her. Next shot of Meg shows a plate of food appear out of nowhere. Peter, Lois and Chris had a plate in front of them and there was no plate in front of Meg at any time. There was no other food in sight on the counter or stove either. (00:15:00)
Partial Terms of Endearment - S8-E21
Continuity mistake: In this episode, Lois is shown to have dated Naomi during college. But in the episode "Meet The Quagmires", it was established that Lois and Peter were already dating when Lois was eighteen. She accepted Peter's marriage proposal at that age. She would have been engaged and possibly married during college, not dating other people.
Other mistake: Lois goes to the bathroom at the bowling alley. There's only one way to the bathroom yet Quagmire beats her there and has time to hide in the stall. There's no way he could've done that considering he went after Lois.
The Thin White Line (1) - S3-E1
Other mistake: During the scene at the rehab clinic when Brian is jogging, Peter asks if he wants to go "mess with the pregnant teens across the lake." Brian says no because "Group therapy, two o'clock." However, the sky looks as if the sun is about to rise or just set. The time cannot be anywhere close to 2:00, neither AM nor PM.
Factual error: Peter is posing as a blow up sex doll. The tester picks him up like he doesn't weigh anything. Not possible.
Continuity mistake: Peter falls from the roof of the Clam landing on Joan Cusack. He puts her body in a mailbox that appears just for this scene.
Road to the Multiverse - S8-E1
Other mistake: In every universe - except for the double-headed universe - Brian and Stewie travel to, they (seem to) replace the version of themselves that universe already has of them, but then in the Dog universe they have a separate version of themselves that they continuously interact with.
Ocean's Three and a Half - S7-E7
Factual error: Bonnie changes Susie and Joes diaper. There's no way Joe wears the same size diaper as Susie.
Boys Do Cry - S5-E15
Other mistake: Towards the very end, they automatically head to the car, planning to leave Texas, without any of their items from the house packed in the car after running away from the mob at the Miss Pageant Contest.
A Picture Is Worth 1,000 Bucks - S2-E11
Other mistake: Brian says he met Antonio Monatti when he was with Andy Warhol in the '70s. This is an impossibility. Only several episodes earlier (in episode Brian in Love), we find out that Brian is 7 years old.
Answer: Lacey Chabert was the actress who originally voiced Meg in early episodes. She left of her own accord due to being in school and other acting work; Seth MacFarlane has stated there was no tension with her leaving, but it makes for a handy joke for the show.
Jon Sandys ★