Continuity mistake: Just after the girls are quarantined, we see the ninja sneak into the little boy's room. He uses the sword to keep the door from closing, and some blood drips onto the floor. Two shots later, we see the same floor and the blood is gone.
I've Got You Under My Skin - S1-E2
Continuity mistake: In the previous episode, Piper tried out for a job as a chef at a restaurant called "L'Opera Ristorante" and was hired by Chef Moore. Then in this episode, she works at a bar and restaurant called "Quake," but she talks about Chef Moore quitting and leaving her in charge of the establishment, so it's not meant to be a different place.
Witchstock - S6-E11
Plot hole: This episode takes place in 1967, and Penny (Grams) is married to a man named Allen Halliwell who dies in the episode. Allen is supposed to be Penny's "first husband," Patty's father and the Charmed Ones' grandfather. But it was previously established that Patty's father was named Jack, and he died in 1964. Also they hint that Patty is still little but we know she was born in 1950 so she would be 17.
Continuity mistake: When Paige follows Phoebe into the kitchen and is trying to convince her that she is telling the truth, Phoebe's right earring is missing in the shots showing both women, but it is there when the shot changes to close ups of Phoebe. It is an awfully large earring to be hidden by her hair in the two-shot. (00:25:20)
Plot hole: Rick is menacing Phoebe with a gun near the end of the episode. Why doesn't Paige orb the gun away from him? In fact, why did Phoebe make Piper stay upstairs? Piper could have frozen Rick, and Paige could have orbed him back to the prison. There were several obvious ways to resolve this situation that would not have caused Rick's death.
Size Matters - S4-E5
Continuity mistake: Shortly after Phoebe frees the blonde girl from the clay, she tells her to run "before Gammill sees [them]." But Phoebe hadn't learned the demon's name at any point. Leo and Piper do find out his name, but not until later. (00:20:00)
Suggested correction: Gamill and Finn are talking when Phoebe is at the house. It may be possible that Gamill's name was mentioned by Finn in conversation.
Continuity mistake: You'll notice in some episodes (like "Coyote Piper") that when the sisters look out of the attic window, they can see Prescott Street below, indicating that the attic window is on the front of the house. But if you look at the size and shape of this window, you'll see that there is no window like this on the outside front of the house. In addition, in "Sin Francisco," Phoebe looks out the attic window and sees the front porch from a side view. There's no structure on that side of the house to begin with.
Plot hole: Piper is initially skeptical at Phoebe's theory that the Evil Enchantress could be Paige in a past life, because Paige lacks the Enchantress' ability to summon the elements. However, Piper knows that in Phoebe's past life she had a pyrokinetic power, which she does not have in the present.
Suggested correction: This is not a correction, more of an observation that goes with this plot hole. In season 2 episode 14 'Pardon My Past' Leo explains to the sisters that Phoebe had her active powers taken away, because her past self had used them for evil, but yet the Enchantress does the same with her powers, and Paige still has active powers. It took two years for Phoebe fighting as a good witch to actually gain an active power again, and then it was only levitating. Becoming an empath took seven years. So that doesn't really make sense that Phoebe would be punished for her past self actions and Paige was not.
Possibly Paige had past lives in between the one we saw and the present one. So she could have already atoned for the evil past life in another past life.
Also Paige's active power comes from her Whitelighter side not her witch side, she doesn't have any active witch powers.
Paige's active power comes from her whitelighter heritage, so like Chris and Wyatt, she doesn't have an active witch power, so this active power has nothing to do with her Wiccan heritage and past life as the enchantress.
Plot hole: It's shown with the spell that the Halliwells leave for Chris in the attic that if something happens in the past, the future will immediately reflect that change. Chris had changed so much in the past that there should have been at least one thing different that mildly surprised him, even if he was careful to not give too much information to the sisters about the future.
The Power of Three Blondes - S6-E4
Continuity mistake: The Stillman sisters strip the Charmed Ones' powers by using the same spell as Aunt Gail did in Season 2 (How to Make a Quilt out of Americans). But in that episode the Charmed Ones had to first drink a potion and Aunt Gail needed to wait a certain amount of time (at least 30 minutes) before the spell worked. In The Power of Three Blondes, the Charmed Ones never drank a potion and lost their powers before the Stillman sisters even finished the spell.
Magic Hour - S3-E2
Continuity mistake: In this episode, Phoebe says "Grams, you were married four times." But in "Lost and Bound," Phoebe tells Cole that Grams was married six times.
Continuity mistake: When Prue was talking with the shut-in and the security guard comes up and knocks on the door you can see the the chain is on the door. When he knocks again and says he is coming in and tries to open the door the chain is off.
Revealing mistake: When Phoebe goes to sign her papers at the end, she spells her name as Pheobe. (01:22:45)
Continuity mistake: When Adam spills coffee all over Phoebe's top in the office, the stain disappears and reappears between shots. (00:08:05)
Continuity mistake: For season 7, episode 5. In the beginning, Piper is wearing a top with the blue skinny strap on her right. For the rest of the episode, you can see the strap on her left.
Continuity mistake: 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. (00:11:05)
The Truth Is Out There... and It Hurts - S1-E8
Continuity mistake: In the teaser, the demon attacks Dr. Mitchell, killing him and also destroying his irises. His eyes turn white, and later dialogue confirms that the irises were gone from his eyes. However, when the Charmed Ones find his corpse, his eyes are open and his irises are visible. (00:01:10)