Artie Ziff is shocked to learn that Marge Bouvier is married. Yet in the previous scene, he referred to her by her married name, Marge Simpson. During season 4, Artie also ran into Homer and Marge at their high school reunion.
Artie Ziff is seen sitting next to a large picture window overlooking Silicon Valley while searching his e-mail. When he sees the e-mail from Marge, the camera angle changes and the window is gone, and we see Artie completely surrounded by photos of Marge.
After Artie reads Marge's e-mail you can see the computer is off.
When Homer and Marge are lying in bed and Homer suggests that Marge stays with Artie for the weekend, the clock changes from 2:00 to 10:10.
At the opening theme in the garage, you can hear Marge's car stop but Marge's car still moves.
When Artie sees Marge in her blue dress, she says "Hey, Artie". But her mouth keeps moving after she's finished talking.
Before Marge and Artie "go back in time", Marge says "Were are you taking me?". Her mouth doesn't match what she's saying.
When Marge and Artie are at their prom reinacment, the band singer's mouth doesn't move when she sings.