The One With Rachel's Date - S8-E5
Revealing mistake: In the scene in the coffee house, Phoebe is talking to Monica who is drinking a cup of coffee. Towards the end of the scene, the camera is on Phoebe who is smiling and laughing at Monica. In the right-hand corner is a side view of 'Monica'; however, it is not Courteney Cox in the scene but a completely different actress. [Widescreen version only, although the "wrong" nose is visible in the original]. (00:06:20)
Revealing mistake: When he's attacked in Down Below, Dr. Franklin is shoved against a station bulkhead/wall that wobbles when he hits it. (00:15:30)
Revealing mistake: After Mark gives his father the keys and tells him to park the van, in a following shot when Elizabeth joins the gurney rush with Carter, as she's walking backwards there's a distinctive large bulge at the back of her waist from the mic transmitter. (00:10:55)
Sins of the Fathers Chapter 1: Doctor Strange - S3-E1
Revealing mistake: When Mary Jane and the other servants of Baron Mordo are flying through the city, they literally disappear into thin air. Probably a problem with rendering the 2D animation within the 3D animation. (00:01:00)
Revealing mistake: When Ellen and the rest are on the ski lift, it becomes apparent that they are being filmed in front of a green screen because as the lift chair in front of them sways back and forth it disappears into it on the left side. (00:02:05)
Revealing mistake: When Nova blasts through the building, the wall where the hole is created has already been drawn as misshapen and discolored, likely to make it easier for the animators to animate. (00:02:53)
Life Lessons - S1-E4
Revealing mistake: When Danziger and True are pursuing Gaal, they drive up next to Gaal and his horse. In several shots it's obvious it isn't Danziger driving, but a stunt double. (00:47:10)
Enemy Within, Enemy Without - S1-E6
Revealing mistake: When Iron Man tells MODOK that his wife is waiting to see him, MODOK's nose and a section of his headband are briefly missing from his face. (00:19:49)