Continuity mistake: At the start, Chris' hat is all yellow instead of yellow and black. (00:00:30)
Jungle Love - S4-E13
Other mistake: In the kitchen when Peter is playing with the paddle ball and then Brian confesses to giving Chris the idea about joining the Peace Corp, there is a picture frame on the wall behind Peter. In this is various pictures of the family including Brian. In this, Brian is as a yellow dog despite being white in the series, and even in the scene depicted.
Brian Writes a Bestseller - S9-E6
Continuity mistake: When Stewie answers the door, notice the doorknob. It's down further in just this scene, so he can answer it. The rest of the episode it's where it's supposed to be.
Baby, You Knock Me Out - S9-E5
Factual error: Peter gets a record a message card from Cleveland. He hears a conversation, hears him driving and get pulled over by a cop. Impossible since the card stops recording as soon as you close it.
Other mistake: After Brian says Chris is tweaked and Chris says maybe the toad is Meg's, the bubbles in the aquarium stop moving.
Other mistake: In the flashback to Brian and Peter playing checkers, Brian's piece is not on the back row when he says "king me."
Continuity mistake: Lois and Brian go outside and celebrate Peters dads death. Behind them you see the trash cans. They come back in and sit down and the trash cans have vanished. (00:12:33 - 00:12:54)
Peter, Peter, Caviar Eater - S2-E1
Continuity mistake: When Brian is holding Peter's Star Wars glass, it continually spins and changes positions in his hand between shots, with the figures painted on it being in different directions. (00:17:32)
Continuity mistake: At the start in class there are two people behind Meg who both have green tops. When the camera shows the class from the front one of the green tops has changed colour. (00:02:05)
Continuity mistake: Going up the ladder Lois has Stewie in her left arm. However, as she comes through the window he is in her right arm. (00:06:00)
Continuity mistake: When Joe lifts his steak to his mouth you can see a section cut out of the steak on the plate. When he shoots the plate, the steak is whole. (00:01:50)
Brian Goes Back to College - S4-E15
Continuity mistake: When Stewie runs in to film Brian after he got fired, Lois has her arms crossed. When we see it from the camera's POV, her arms are in completely differently positions. (00:07:10)
Brian Goes Back to College - S4-E15
Continuity mistake: At the start Stewie is sat in the middle of the middle cushion on the sofa. However, as Lois walks off he is now sat on the join of two cushions nearest Brian. (00:02:25)
Continuity mistake: When Meg tells her family she's a lesbian, Lois has food on her spoon. As Meg starts yelling about her friends liking her, Lois is holding a fork with no food on it. (00:11:40)
Continuity mistake: As the trio are singing at the end, the position of the 3 changes between instant cuts. (00:20:05)
Continuity mistake: When Neil points out the poster for Meg, Meg has 2 books in her arms that become one. (00:04:20)
Revealing mistake: Watch closely when Brian is demonstrating orbit. The apple can be seen to go through Peter's hand a couple of times. (00:07:50)
Continuity mistake: The fork with steak on it that's on Joes plate disappears between shots. (00:02:05)
Continuity mistake: At the steakhouse before Joe shoots the table we see Peter's knife on his plate but it suddenly appears on the table. (00:02:00)
Answer: Mort is Jewish, and Walt Disney was said to be antisemitic. So it would make sense in a Disney universe all the inhabitants would share his supposed beliefs.