Wicca Envy - S1-E10
Visible crew/equipment: After Jaime tells Prue that she's the hardest working woman he's ever met and believes she's innocent, Prue walks into the office to access Hannah's computer, and just as Prue sits down and moves closer to the desk, the blue T-mark is visible on the floor, under the office chair. (00:24:30)
Wicca Envy - S1-E10
Continuity mistake: At the end of the episode, when Leo and Piper are saying goodbye he reaches out and touches her face, but when the angle changes his hands are instantly back at his side. (00:43:05)
Wicca Envy - S1-E10
Audio problem: When talking about the tiara with a security guard Prue's mouth stops moving mid sentence but the audio continues.
The Wendigo - S1-E12
Visible crew/equipment: When Phoebe joins her sisters in the kitchen before her first day at work, the reflection of the moving boom mic is visible on the glass cabinet, at the top of the screen. (00:10:05)
The Wendigo - S1-E12
Continuity mistake: When Andy is lying on the ground unconscious The Wendigo rips open his shirt popping all the buttons, but in the closeup of Andy's face his shirt is still buttoned up. (00:38:50)
From Fear to Eternity - S1-E13
Visible crew/equipment: When Andy walks into the manor to speak with Prue, just as she tells him it must be bad news, we see the reflection of the boom mic on the glass door. (00:09:45)
From Fear to Eternity - S1-E13
Plot hole: Prue finds an entry in the book of shadows about the fear demon written by her mother. How would her mother know anything about this demon when no one has seen him in nearly 1300 years, let alone how to defeat him?
From Fear to Eternity - S1-E13
Other mistake: No one, including the cops, seem to think that all the victims' hair turned white is strange, as if getting scared to death actually turned your hair white.
Continuity mistake: In this episode, Leo tells Phoebe that white lighters are sent to their charges by "a group of elder white lighters known as the founders." However, by later seasons in the series, the word "founders" was never used. The leaders of the white lighters were simply known as the "elders." (00:14:15)
Is There a Woogy in the House? - S1-E15
Continuity mistake: At the beginning of the final scene in the attic, the view from the window prominently features the Transamerica Pyramid. At the end of the scene, the view is completely different, showing the Ferry Building and the Bay Bridge. (00:41:30)
Is There a Woogy in the House? - S1-E15
Continuity mistake: At the beginning and throughout most of the episode you can see the entrance to the basement. If you look to the right of the door you can see a light switch by the door with the cover on it. At the end of the episode they show the entrance but this time the cover to the light switch is off.
Which Prue Is It, Anyway? - S1-E16
Continuity mistake: While Phoebe explains the slam man training system Piper puts on Phoebe's boxing gloves, and when Prue says that demons don't play fair Piper playfully raises her left arm to Prue's forehead, but in the next shot facing Prue it's Piper's right arm that's raised. (00:04:00)
Which Prue Is It, Anyway? - S1-E16
Continuity mistake: When Prue goes up to cast the spell, Piper and Phoebe are downstairs and Piper's hair is down. When they hear the effects of the spell they run in to the attic and both say "Oh my god!" one after the other and Piper's hair is now slicked back in a ponytail.
Which Prue Is It, Anyway? - S1-E16
Revealing mistake: When Pink Prue is stabbed, they show the warlord over her, with the sword supposedly having stabbed her body. It is very obvious that the sword is not actually in her, but about a foot away from her body, closer to the warlord.
Continuity mistake: In this episode, the sisters go back in time to late March 1975. On the family tree it says that Piper was born on August 7, 1973. So she would be 1 and 1/2 in March 1975. But she looks at least 2 years too old. (00:09:30)
Plot hole: Throughout the series, it's established that good witches don't freeze. In this episode, however, Little Piper freezes Future Prue and Piper when they come back to the manor to "kidnap" their younger selves. Simply because the Charmed Ones reason that only one "set" of sisters (past/future) could have their powers doesn't mean that Future Prue, Piper and Phoebe aren't good witches. In other time-travel episodes, the sisters remain immune to freezing and are still able to say spells make potions, meaning they are still good witches. For example, in Season 8 "Forever Charmed," Piper and Leo go back to 1975 (the same time-period as this episode) using Coop's ring, trying to find when Phoebe is alive again. However, when a startled Patty tries to freeze them, only Leo freezes. Piper does not, though she likely cannot use her freezing/exploding power in this time.
Factual error: Little Piper (from 1975) has blue eyes. She should have brown eyes, like present day Piper.
Other mistake: Grams says that if she died the girls would automatically get their powers; but they got their powers 6 months later and Phoebe had to read from the book of shadows first. Not really automatically.
Revealing mistake: In the scene where Penny uses her powers at Nicholas and throws him on the dining table, it is clear that the table is a fake one simply made of simple wooden boards.
Answer: That was a mistake in the series.
Also, the episode is called 'Babies First Demon' and this alone tells us that it's Wyatt's first time in the field (so to speak) and as the sisters say, they've done a good job of clearing up their own magical messes so far. Nobody really knows how advanced Wyatt's powers are, or will become. That's why the cleaners appear, to nip things in the bud. The Cleaners didn't want to chance that the sisters could clean Wyatt's magic up, just incase they couldn't. Therefore intervening themselves, just in case.