Plot hole: Cole explains that the demonic power is driving Karen mad because she is human. Cole later has Paige infected with one to drive her mad. This doesn't make sense since Paige is doubly not human, and shouldn't be driven mad. In fact the Charmed Ones have had demonic powers before and were not driven mad, but instead turned evil.
Visible crew/equipment: When Phoebe tells Piper that she's on a deadline and hangs up the phone, in the next shot as Piper says that she's going to Phoebe at the newspaper, the shadow of the boom pole/mic can be seen on the wall behind Piper, at the top of the screen. (00:26:45)