Siren Song - S5-E4
Character mistake: When discussing how best to help Melissa, Piper tells Paige that her birth father was half whitelighter, when he was fully a whitelighter. (00:25:15)
Character mistake: When Miles is shot, the cops apparently don't think it's necessary to tend to him to see if he's okay.
Character mistake: Paige goes undercover into the demonic market wearing a bright blue dress and blond wig, and none of the demons seem to notice she sticks out like a sore thumb.