Continuity mistake: When Seth tells Carrie that Dr. G's plant is plastic his hand is either holding the glass or not. This changes back and forth.
Continuity mistake: When Carrie talks about his first date with Seth there's an aerial shot of him holding a drink and taking a sip. A shot later he is not holding the glass.
Continuity mistake: When Stanford tells Carrie that she has to have a shrink, a man suddenly appears behind and the kid next to him changes positions between angles.
Answer: I'm a long-time fan of the show, having re-watched it many times, and I definitely remember slightly different dialogue at the end of that episode than what's on my DVD. I'm afraid I have no idea why this change might have been made or any other info, but you're not insane.
Purple_Girl