Continuity mistake: Carrie cries out "where are our drinks!" and Samantha (yellow glass) turns around and raises her arms to call the waiter. But a shot later her arms are on the table next to her glass.
Continuity mistake: Right before and the moment where the girls sing 'Memories' the cigarette package on the table keeps changing positions in every shot.
Continuity mistake: During cocktails, Carrie says "there are 2 type of girls" then two guys in a suit walk by behind her. In the following shot they disappear.
Continuity mistake: Carrie holds the wedding invitation form the upper part, then from the side and then from the upper part again, depending on the shot.
Revealing mistake: When Samantha tells Mr Cocky to be nice and easy she is not naked, but wearing skin-coloured underwear.
Continuity mistake: After Carrie knocks the chair over, napkins suddenly appear on the table.
Continuity mistake: When Carrie leaves lunch with Big the little rolled paper on the table changes positions between shots.
Continuity mistake: When Carrie cries "Engaged!" her hands are holding her head, but from the opposite angle they disappear.
Continuity mistake: When Carrie says she hates Blood, sweat and tears, Big's hand swaps between being on the table or on the edge of the table or off the table, between shots.
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