Corrected entry: After the shapeshifter turned from a mailman into Andy, Prue told him about her father returning to town. Later, the real Andy came to the house, and then after a cut, he and Prue were talking about Prue's father, Victor. Andy has known Prue since high school, and therefore knows that Victor has been gone for twenty years. And since Prue only told the shapeshifter about Victor's return, the real Andy didn't know about it. So how could he and Prue have gotten onto the subject of Victor being in San Francisco, a fact that surely would have surprised the real Andy, without Prue figuring out that Andy wasn't the one she talked to earlier that day?
Corrected entry: In this episode, their father recalls that Piper once upon a time would only eat white food. She says, "That's right. I was four." And then their father says "Phoebe, that would make you what, one?" And Phoebe says, "Yeah." But in other episodes, if you look on their family tree, Piper was born in 1973 and Phoebe in 1975. So she would be two, not one.