Chick Flick - S2-E18
Continuity mistake: In the teaser, Phoebe took off her messenger bag while she was sitting in the chair talking to Prue, and she left it there when she went up to get the door. For the rest of the scene at the house, including when Phoebe and Prue ran out of the door, Phoebe was not wearing the bag. Then, when we saw them outside immediately thereafter, Phoebe was wearing the bag again.
Chick Flick - S2-E18
Continuity mistake: After Phoebe kisses Billy, she sees that the makeup over his lips has washed off and that they're in black and white again. While she applies more to him, the phone rings, Billy turns his head, and his lips are normal. In the next shot, they're back to being in black and white. (00:22:15)
Chick Flick - S2-E18
Character mistake: After the horror movie characters were killed in the attic, the sisters hear the door bell ringing. When they get to the bottom of the stairs and start walking towards the front door, you can see the actor playing Billy smiling even though they're all supposed to be on edge.
Chosen answer: Her agent/manager negotiated a special billing as part of her contract. It distinguishes her from the rest of the cast, probably when she became a producer on the show.
JC Fernandez