Nikolai

The Mook, the Chef, the Wife, and Her Homer - S18-E1

Revealing mistake: When Fat Tony says "The Calabresis. My archenemies in waste management." while driving the carpool, a huge line briefly appears around his cheek and mouth.

White Christmas Blues - S25-E8

Continuity mistake: While Mayor Quimby is giving his speech, Moe is in two places at once. He is simultaneously standing next to Mayor Quimby and amongst the crowd of people.

Nikolai

Tree House of Horror X - S11-E4

Continuity mistake: In "I Know What You Diddly-Iddly Did", Marge's necklace keeps changing from red to white when the Simpsons are at church, and when they go back home.

Nikolai

The Telltale Head - S1-E8

Revealing mistake: When Barney says "How long will the story take?" after Bart offers to tell the mob his story, the upper half of Barney's face starting from his nose is a darker shade of yellow than his lower half. His shirt also changes colour. (00:01:40)

Bart the General - S1-E5

Continuity mistake: At the end when Nelson's goons are holding on to Nelson, they both have brown skin. But in the next shot, one of them goes back to having yellow skin.

Homer the Vigilante - S5-E11

Revealing mistake: When everyone is cheering for Ned at the neighborhood watch meeting, Apu's hand is yellow.

Bart Gets Hit By a Car - S2-E10

Revealing mistake: After Marge has been in court, Mr Burns' lawyer says "Thank you very much Mrs Simpson", and when he does it, the top of his head above his glasses is less pale than the rest of his face.

OL1V3R666

Bart's Comet - S6-E14

Continuity mistake: At the end of the episode, when we see a wide shot of everyone going to join Ned on the hill (and singing the song) look to the far left. You will see Apu - and his skin is yellow.