Womb Raider - S4-E21
Other mistake: Piper tells Page that her doctor told her she probably wouldn't be able to conceive because of scar tissue from blunt force trauma. But Leo has healed Piper, if there was scar tissue after Leo heals, then all 3 girls should be covered in scars.
Suggested correction: They are thrown around quite a bit before even finding out Leo is a whitelighter. Also, he doesn't heal them every time they get thrown or hit in the abdomen. In fact, we usually don't see him heal them at all if they're just thrown across the room or punched in the gut, unless there's a visible wound.
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.
The Truth Is Out There... and It Hurts - S1-E8
Revealing mistake: When Phoebe asks Piper what she thinks of her boss, you can see that Holly's tattoo has been covered up, because that part of her wrist is darker than her skin. (00:17:15)
Suggested correction: Maybe Holly covered it up with makeup because she isn't supposed to have tattoos for her job? A lot of jobs still don't allow piercings and tattoos today but all those years ago it was even harsher.
There are multiple instances of covered tattoos during the early seasons. I noticed it the most on Alyssa's back tattoo.
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.
Suggested correction: They all are human, just not mortals.
Corrected entry: The sisters act as though they have never heard of the evil eye before; but in episode 1-2 'I've Got You Under My Skin' the demon Javna invokes the power of the evil eye to steal youth from women.
Correction: Javna is the Charmed Ones' second vanquish, so it isn't all that unreasonable to assume they didn't know (or remember) that Javna's power was "the evil eye" since they were so new to the craft. They used the Hand of Fatima to vanquish him, and no "evil eye" was mentioned in 1-2 "I've Got You Under My Skin."
Correction: The evil eye was mentioned by Prue when they read the Javna entry.
Continuity mistake: In the recording that Agent Jackman plays for the sisters, the end of the reversal spell is heard "bring her back to me," but when Paige and Piper said it moments earlier, they only said "bring her back." (00:17:45 - 00:19:10)
Suggested correction: They say "bring her back to me" both times.
Size Matters - S4-E5
Other mistake: Since when are managers, on a trial basis no less, allowed to renovate and change the name of a club?
Suggested correction: Piper says in the episode that she allowed him creative control because the club wasn't doing well, and he was well-known to be good at what he does. It's made clear throughout the episode, by way of him telling her multiple times that if she doesn't like it that he'll get rid of it, that she still has full veto power on any changes.
Plot hole: When Yen lo enters the manor in the attic. Where did the water on the floor he comes through come from? Windows were closed, no visible leak, and the sister took precautions to make sure there was no water in the house. Also after he attacks and gets the dragon blade, he exits the house through the sink filled with water. Piper had already said to make sure there was no surfaces of water in the house and had Phoebe and Paige shut the water main off.
Suggested correction: There is a previous scene that shows a visible leak in the windows and an obvious puddle of water on the floor of the attic. This is the same puddle they later enter limbo through. As for the sink, Phoebe (in Paige's body) explains that she had been soaking potion pots and forgot to drain the sink. Turning off the valve wouldn't dissipate water that is already in the sink.