Audio problem: Baby Matthew is supposed to be screaming his head off, when Prue levitated the contents of her purse to cheer him up. But she turns him to the camera and he is smiling. (00:21:40)
Visible crew/equipment: While Phoebe is telling Prue about the abandoned baby, Piper comments that the baby is like a car alarm, and as the sisters walk into the foyer the white T-mark is visible on the rug in the foyer. (00:07:20)
Continuity mistake: When Matthew starts crying and Piper freezes him, Prue puts her hands on her forehead. In the following close up, her hands are brushing her hair back, then back on her forehead in the next wide shot. (00:23:00)
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