Audio problem: When Joey is proposing to Rachel and he tells Phoebe to give him the ring back, she says "No!" and pulls her hand away. When she pulls it away, she hits her chest and there's a thump sound that's clearly the sound of her clip on microphone being hit (it's way too audible to be just a thump on her chest). (00:17:50)
Audio problem: As the nurse comes back from wrapping the new baby, we hear her say "Here she is," yet her mouth doesn't move to the words she is apparently saying. Even though her mouth is only visible during the "she is", she's not saying the words. Then she mouths some sort of "oh", but nothing is heard. (00:09:00)
Audio problem: While the adoption social worker, Laura, is interviewing Monica and Chandler, Monica mentions to her that she's welcome to look under any of the furniture where she won't find cigarettes or porn, and then it cuts to Laura's close-up as we hear her say, "Well, actually before we look around," but her mouth is not saying those words.
Audio problem: When Rachel asks Barry and Mindy why people keep telling her to 'get well soon' and Barry says his parents told everyone she has syphilis, and in the next shot it shows Rachel trying to take this information in, Barry seems to still be talking, but no sound is coming out of his mouth. (00:09:25)
Audio problem: When Joey walks out of the bedroom dressed as a 19 year old, when Chandler says the line "Yes, on a scale from 1 to 10, 10 being the dumbest a person can look, you are definitely 19", you can see that the audio doesn't match the words. It looks as though Matthew Perry says "not 19" and they had to re-dub over post production with "19." Subtle, but it's there. (00:08:50)