Other mistake: When Bree goes to talk to Eddie Orlofsky's mother, she introduces herself as "Bree Hodge." However, she proceeds to talk about how Eddie likes her daughter Danielle, but her daughter "doesn't return his feelings, she spends most of her time with the other cheerleaders." In the scene before, Eddie had also mentioned that he liked a girl "from school." The problem is at the time that Danielle was in high school, Bree was not "Bree Hodge", but "Bree Van de Kamp." She hadn't even met Orson Hodge then. (00:19:10)
Continuity mistake: Throughout the series, any time you see into the front door of the Scavo house (from an exterior shot), there is a blue wall with a table in front of it, however, interior shots show that the front door leads to the lounge, with the staircase opposite the door.
Plot hole: Several days must have passed between the teaser of this episode and the rest of it, since Gabrielle has had time to make up (very professional-looking) cards and posters, gotten several dozen volunteers and reserved dresses for many of them, yet Paul has only just gotten around to disposing of Mrs. Huber's body and trying to wash the blood out of his shirt. Even if we assume the teaser takes place right after the end of the last episode (when Paul murdered her), that's still several days of keeping a rotting corpse and enough evidence to put him away for life around his house.
Mother Said - S4-E15
Continuity mistake: When Orson is on the phone with his lawyer, he sets down the notepad with a page half filled with writing at the front. However, later in the scene Edie walks into the room and the front page of the notepad is full of writing, plus there's an extra line in the first paragraph. No one was around to move the page as Orson was in the shower.
You'll Never Get Away From Me - S2-E3
Continuity mistake: Gabrielle sits down with some letters in his hands then places them to his right side while she is talking to John, first the letters are mixed up and then in order. (00:26:30)
Visible crew/equipment: In one of the episodes, Gabby has her Maserati car taken from her by the repo guy. When he pulls off, the car is towed behind him. Clearly reflected in the metallic paint of the Maserati is the crew, with boom, camera and everything else.
Continuity mistake: When Lynette gives her husband his photo, the position of the photo changes in between shots. (00:13:05)
Every Day a Little Death - S1-E12
Continuity mistake: Bree arrives home carrying a package in her left hand and bags in her right. In the next shot, when her phone rings, the package is gone, the bags are in her left hand and she answers the phone with her right. (00:07:10)
Continuity mistake: When Gabrielle and Carlos go out of the house to investigate what is happening when the Chinese maid starts shouting, they close the door behind them. In the following shots the door is open again.
Continuity mistake: When Karl is speaking to Susan whilst she's in the towel, we see in one shot his chin is resting on his palm, then when the shot changes he tilts his head and then moves his fingers to his chin then when the shot changes his chin is resting on his palm again. (00:25:00)
Continuity mistake: When Bree is talking to Lynette about what Lynette would say to Andrew's lawyer, in the shots facing Bree her right hand is on top of her arm, but from behind, her hand is under her arm. This happens again in the next shots.
We're Gonna Be All Right - S2-E12
Factual error: When Susan has an MRI scan she walks into the scanning room with the radiographer wearing jeans and an underwire bra, both of which are not to be worn in the scanning room due to the power of the magnet which would pull her towards the scanner. She also is carrying her handbag which also would be pulled against the scanner. She is left fully clothed as she enters the scanner, wearing the under-wire bra would pin her down to the scanner. A coil must also be wrapped around the area being looked at so that images can be obtained, she did not have anywhere near her body. The radiographer also had pens in his pocket which would easily fly out and towards the scanner.
Continuity mistake: After Caleb thinks he has killed Melanie, he wipes his right hand across his T-shirt several times and leaves one bloody handprint. When he gets home, there are now several bloody prints from his right hand on the T-shirt.
Your Fault - S1-E13
Audio problem: At the school dance, the students are all dancing at a rapid pace when the music playing is a slow song, indicative that the music was dubbed in later.
Impossible - S1-E15
Continuity mistake: Episode 15- When the housewives are sitting on the porch discussing Mike Delfino, Teri Hatcher's green shirt keeps changing positions in the shot. It goes from down around shoulders to close to her neck and back.
Factual error: This is for one episode 1-23. In the beginning, there is a shot of a calendar for March 1990. It shows March 1st being a Wednesday. March 1, 1990 was a Thursday.
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Continuity mistake: When Susan's reading her Valentine's card, in the shot over her shoulder she closes it. The angle then changes so we can see one of the other housewives approaching - her card's now open and she shuts it again.
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Continuity mistake: Bree Van De Kamp is sitting in a chair talking to her husband Rex while knitting. In one shot, after the camera goes back to her, the object that she is knitting disappears, then re-appears when the camera comes back to her later in the scene.
Continuity mistake: When Nora dies, Lynette stands up and strokes her hand over her chin, so a little blood stays on her chin. During the yelling scene of Lynette towards Carolyn, the blood on her chin changes constantly between shots.
Continuity mistake: When Mike is taking his dog to the vet, we see that Susan's hair is covering her ear in all the shots except the last one when her hair is behind her ear to show that the earring is gone. (00:39:30)
Answer: Kayla was sent away in episode 16 (The Gun Song) in season 4, after falsely accusing Lynette of child abuse. She now lives with her grandparents - probably Nora's parents.
I'm curious why we never see her again, why she never talked about, and why Tom never mentions visiting her.