The One In Barbados, part 2 - S9-E24
Other mistake: The layout of the hotel surrounding the main cast's rooms as displayed during the sequence where Monica, Chandler, and Phoebe eavesdrop on Ross, Charlie, Rachael, and Joey is physically impossible. Ross enters the room Monica, Chandler, and Phoebe are in through the same wall they are using to listen in on Charlie and him, though while the camera is in Ross and Charlie's room, no door can be seen in that wall. Furthermore, a hallway can be seen through the doorway while Ross holds the door open, implying that the two rooms do not share a wall in the first place.
The One With Rachel's Other Sister - S9-E8
Other mistake: When Joey and Phoebe are talking while Rachel and Amy are fighting, Phoebe says the line 'Oh my God. Shouldn't we stop this?', Joey is mouthing her lines. (00:20:25)
The One With the Sharks - S9-E4
Other mistake: While Monica, Rachel, and Joey are seated at the table talking about Joey's problem, there's a Dasani water bottle on the table with part of the brand name painted black so it reads "Asav" on the label.
The One With Ross's Inappropriate Song - S9-E7
Other mistake: When Joey and Chandler are watching Richard's sex tape the screen is off right before Monica comes in, and yet she sees the video playing (you can still hear sex noises with the screen off). (00:14:40)
The One With Ross's Inappropriate Song - S9-E7
Other mistake: When Chandler finds out that the video marked 'Monica' is just a football game he says, 'This may be the first time I have enjoyed football.' Although in 'TOW The Football' (season 3) he is quite happily watching the Thanksgiving Day game with Ross and Joey.
The One With The Soap Opera Party - S9-E20
Other mistake: In the opening credits, the word "Teleplay" is misspelled as "Telelplay."
The One With The Soap Opera Party - S9-E20
Other mistake: When Rachel walks in to her apartment right before the message of Jan Rogers, you can see the hole in the wall where the board usually is.
