Continuity mistake: Episode 8x17, "Generation Hex": When Phoebe and Cupid visit the memory of Phoebe revealing she is a witch to Dex, past-Phoebe has her hands down by her sides, but then her left hand suddenly jumps to her purse strap. Not only that, but in the original episode ("Rewitched"), Phoebe's hand remained on her purse strap the entire time.
Continuity mistake: After the Grimlock kidnaps the child getting the ball, Prue goes after it. But the demon opens a hole in the earth and jumps through it and it closes. Prue then reaches the spot where the Grimlock disappeared and she is surrounded by dead leaves and trees. Then it goes to another shot of Prue turning around. Suddenly the trees and dead leaves are gone and she is standing in an open area with green grass and no trees.