Ned 'N' Edna's Blend - S23-E21
Continuity mistake: When Homer (playing Jesus) is on the cross and speaking to Snake, his stubble briefly flickers to yellow twice in the same shot.
A Totally Fun Thing Bart Will Never Do Again - S23-E19
Audio problem: While Bart is in the communication center, the second time Bart says "Squirt!", his lips don't move.
Politically Inept, with Homer Simpson - S23-E10
Revealing mistake: Right before Homer is patted down at the airport, his facial hair briefly flickers yellow.
Politically Inept, with Homer Simpson - S23-E10
Revealing mistake: While Homer catches his underwear with his tongue after the Simpsons' clothes burst out of the suitcases, Homer's tongue briefly passes through his underwear.
The Man in the Blue Flannel Pants - S23-E7
Audio problem: When the woman on the DVD Bart is watching says "Are you sure you're Martin Scorsese?" her mouth is completely out-of-sync with her voice.
The Man in the Blue Flannel Pants - S23-E7
Audio problem: In the rafting scene, while Marge says "And maybe when we get home, we can ride down something else?" part of her dialogue does not match her mouth movements.
The Man in the Blue Flannel Pants - S23-E7
Continuity mistake: While Krusty is talking to his merchandising executives, after Krusty says "Get to the point, unless you want a face full of clown chunks!" part of his collar turns green.
Audio problem: When Homer, Bart and Lisa enter E4, when Homer says "Wow", his mouth doesn't move.
Bart Stops to Smell the Roosevelts - S23-E2
Audio problem: During Superintendent Chalmers' flashback, when he says "So, you are the so-called Breakfast Club?", his mouth movements don't match his voice.
Ned 'N' Edna's Blend - S23-E21
Revealing mistake: When Marge is talking to Helen Lovejoy about Canapés at the party, Marge's mouth disappears for a single frame.
The D'oh-cial Network - S23-E11
Continuity mistake: At one point in court while everyone is laughing, Patty's hair is colored wrong. Her hair is a similar shade of color as Rod and Todd (who are sitting next to her) rather than her own bluish grey hair.
Holidays of Future Passed - S23-E9
Factual error: When Lisa is trying to find Zia on the internet, the Google design shows Doctor Seuss because it is his birthday. Doctor Seuss' birthday is March 2nd. This takes place on December 24th.
Continuity mistake: Milhouse shows Lisa a laptop with e-mails on it. There is also a shot with a list of the e-mails. At no point does anyone click anything, but the next shot shows a different page on the laptop.