Continuity mistake: When Jeff goes into Ian's office and sits down, he puts his book down so the spine is facing the viewer's right and puts his drink on top of it. Later, without touching the book, it is rotated 90°.
Cooperative Calligraphy - S2-E8
Character mistake: Right before Jeff searches Abed's bag, Britta explains to the group that Abed is the innocent one. After Jeff reminds her that Abed put gum in her hair, she looks at no-one in particular and says "empty the bag, Abed." Jeff is the only one holding the bag, with Abed standing five feet away from both of them. It's clear this line was directed to Jeff, but the wrong name was used.
Continuity mistake: The study-room on the second floor of the library, right next to a set of stairs, and the area isn't particularly bright. In the rest of the series, the study room (which is meant to be the same study-room) is now located on the first floor of the library, nowhere near any visible stairs and the area is much brighter and more well-lit. As often happens, the pilot was filmed before any other episode, and the setting was changed in the meantime.
Contemporary American Poultry - S1-E21
Continuity mistake: At the end when Abed is talking to the Dean, there's an open to-go box with chicken fingers. After the Dean asks who would steal a box of hairnets, it cuts back to Abed and the box and ketchup are gone. Post-it notes are also now seen and the stapler moved. In the next shot of Abed, the chicken is back.
Continuity mistake: In the very first shot, we can see there's a man with a dark coat, sunglasses, short hair and earbuds standing directly in front of the dean. When it cuts to the opposite angle, he's no longer there. When it cuts back to the first angle a few shots later, he's suddenly back.
Asian Population Studies - S2-E12
Continuity mistake: Right after the intro, the group is sitting in the Anthropology class waiting for Prof. Duncan. The chalkboard is filed with writing on it. When Duncan enters, the chalkboard is, except for the 3 top-corner titles, completely clean. (00:03:02)
Grifting 101 - S6-E9
Continuity mistake: When the grifting professor and Jeff are speaking in their office after meeting each other, we see the bottle of alcohol change amounts as the camera moves angles (from Jeff's POV to the teacher's). It is lower when the teacher is all alone, and there's more when it's Jeff's POV. (00:20:14 - 00:20:36)
Audio problem: We hear Troy say "you thought" while he is talking to Annie, but his mouth doesn't move. (00:01:15)
Basic Crisis Room Decorum - S6-E3
Visible crew/equipment: While Chang is reading the message about the attack ad, you can see a very visible camera used to film Winger.
Audio problem: A chef is being shot repeatedly by paintballs and heard screaming as he falls. However, his mouth never fully opens for him to scream as intensely as he was. (00:17:30)
Continuity mistake: Britta has a cellphone in her right hand. The camera cuts to behind her and she's flailing her right hand with no phone in it. In the next shot, the phone has jumped to her left hand. (00:13:05)
Laws of Robotics & Party Rights - S6-E5
Continuity mistake: Jeff writes the word "Law" on the board and draws out his "born into dirt" story. A few cuts later, after Garrett asks him when he stopped being funny, the word "Law" looks much different, and the other parts look redrawn. (00:13:30)
Laws of Robotics & Party Rights - S6-E5
Continuity mistake: Jeff is facing Willy as Willy asks him where he was born. Still facing him, he responds, but before he finishes his sentence, the camera cuts and he is how facing completely away from Willy and is drawing on the chalkboard. (00:13:20)
Queer Studies & Advanced Waxing - S6-E4
Audio problem: Elroy walks into the study room complaining about Donkey Kong stealing his idea. We hear him say they made "the eggs into barrels" but his mouth makes completely different movements. (00:00:55)
Lawnmower Maintenance & Postnatal Care - S6-E2
Continuity mistake: Elroy is holding the Dean in virtual reality. In real life, his hand is in front of his face and slightly opened. When the camera cuts closer, his hand is lower and clenched in a tight fist. (00:21:00)
Lawnmower Maintenance & Postnatal Care - S6-E2
Continuity mistake: Britta is running out of her parents' house, leaving the door behind her closing. In the next shot, the door has stopped moving and is opened up more. (00:16:55)
Lawnmower Maintenance & Postnatal Care - S6-E2
Other mistake: Britta hits Abed in the face with a pillow, swinging in from the right, but when it connects, his face swings the other way, the same direction from which the pillow came. (00:16:50)
Continuity mistake: Britta sets down a tray with a sandwich on it horizontally right in front of her. In the next shot, it has now moved further away from her and is sitting vertically. (00:12:05)
Continuity mistake: Chang's sunglasses are sitting on the table in front of Professor Hickey and Shirley. When Richie sits down, the sunglasses have disappeared. (00:10:10)
App Development and Condiments - S5-E8
Continuity mistake: Jeff is doing stand-up comedy with a mic stand an a stool with a bottle of water on it behind him. A few shots later, without touching them or anyone moving them, they all completely vanish. (00:12:55)
Answer: It was part of the plot that when the boiled yam was dropped it looked like it was stepped on (which it never was). So there was no way to tell the difference between the flesh being soft because it was boiled or because it was stepped on (in the show that is, I don't know if one could tell the difference in real life). Plus, the rest of the yam wasn't boiled, so there was no evidence the yam was sitting in boiling water.
Bishop73