In the opening sequence, Prue mentions that "We know 'The Evil Triad' is behind all these attacks", when in fact they were told it was 'The Council', a group of five demons, not three.
Cole places his business card into the pages of one of Phoebe's books. He then turns and walks away as she watches him. When the camera focuses on her again the card is gone. When the camera turns once again to Cole, and then back to her, the card is once more stuck in the pages of the book.
Phoebe hits Cole in his back and he falls forward, however when he later stands up he's touching the back of his head as if he'd taken the blown there.
When Piper came back, Prue said that she was gone for a month. But, at the end when band was playing, Phoebe told Piper she was only gone for 2 days. Based on the context, it was likely a flubbed line that was not caught in editing. Phoebe was likely meant to say that Piper had been back for 2 days and had gotten the band. That makes more sense.