Some EAGLE-EYED Friends fans have taken to social media to call out the 1998 classic episode of Friends; The One With The Embryos, which aired in season four.
It saw duo Monica & Rachel battle Chandler & Joey in what seemingly starts off as a harmless game.
Yet as the game intensifies, the stakes are reaised.
The group decides whichever team wins will get to live in the girls' apartment.
The girls lose - and it is when Monica is bemoaning their situation that eagle-eyed fans noticed something strange.
One commented: "Just after the guys win the trivia game when Rachel is refusing to move, Monica says 'if WE had lost, we would have made them get rid of the birds, right?'
"It doesn't make sense. They did lose. She was probably supposed to say 'if they had lost' or 'if we had won', right?"
Another agreed and added: "I had to stop what I was doing immediately and go check. Yup, both the actual dialogue spoken by Monica and the subtitles say 'if we had lost'. I can't believe the editors didn't catch it!"