When Comet takes the note off the counter, it is not in the same place D.J. left it.
When DJ, Kimmy and Jesse are talking in DJ's room about Kimmy's future and she ends the conversation by saying "let's face it, life together as we know it is over" and leaves the room, she leaves the bedroom door open behind her. In the next shot, the door is about an inch away from being fully closed.
Rebecca says that the Queen autographed the "What to do when you meet the Queen" book for Nelson, but when she shows it to Jesse, the page is clearly blank.
Becky mistakes the earring box for an engagement ring box despite the fact that the two types of boxes would look different inside. One would have two holes for the earrings' pins or hooks while the other protrudes in the center for a ring. Becky would know this.