It Wasn't Meant to Happen - S2-E20
Continuity mistake: At the Hooters style restaurant, Edie intentionally trips the waitress. When the waitress falls, there is a lettuce leaf in the small of her back. When she starts to jump up, the lettuce is now at the base of her neck.
Running to Stand Still - S1-E6
Visible crew/equipment: When Susan is following Paul in the car she borrowed, we can see the reflection of a crew member on the right hand side of the window. (00:18:15)
Audio problem: When Eva Longorea drives home her husband is talking to a man. Their lips move, but no sound comes out.
Factual error: It is the weekend and Valentine's Day. We see in the following episode that it's 2006 and their calendar matches the real one, but Valentine's Day was on Tuesday that year.
Continuity mistake: When Mike comes home with the shopping bag, we see that the items in his shopping bag change positions in between the shots when he goes to see Edie arrive. (00:20:30)
Continuity mistake: When Lynette sits with Gabrielle in the kitchen discussing the kiss, they're drinking shakes. Gabrielle is either holding her shake or it sits on the counter in front of her, repeatedly, depending on camera angle.
Continuity mistake: When Julie is leaving we see that she leaves the door open and then it closes with a slight open gap, yet just for one shot the door is completely closed, then it's open again. (00:09:50)
Factual error: In the ep in season four where Victor drifts ashore, someone calls the police officer at Gabrielle's home and informs him that Victor has been found. The officer answers the call, listens for about one second and then hangs up. In that one second he's gotten four sentences of information to pass on to Gabrielle about her husbands whereabouts. There wouldn't have been time to tell him so much in so little time.
Other mistake: Lynette is talking to Susan about Zach's infatuation with Gaby. Susan asks how Zach can afford so many expensive gifts for Gaby, to which Lynette replies that he inherited his grandfather's money when he "turned 18, a month ago." However, in the previous episode, Zach reminds Gabrielle that he is two months older than John Rowland, who, it was mentioned, turned 18 in season 1, two years before.
Continuity mistake: When Lynette is in the supermarket, right after she loses track of the twins, she is seen pushing her shopping cart down the aisle,and in the seat there's only a pink blanket. But when she sees Nelly Klein, her baby daughter is sitting in the seat with the blanket and one of her sons is riding in the basket.
Continuity mistake: In episode "The Gun Song, Free Part 2," when Gabby runs upstairs to confront Ellie, her headband is further on her head than when she runs into the bedroom.
Continuity mistake: When Rex Van De Kamp is at the restaurant, his fork is half way over his napkin then in a later shot it's completely on the napkin. (00:26:50)
Coming Home (a.k.a. I've Got You Under My Skin) - S2-E10
Continuity mistake: When Carlos is about to be vaccinated, him and Gabby sit in the waiting room. Throughout their conversation watch Gabby's arms. At one point she has them down beside her, then in the next she has them folded. In the following shot they are down again, and in the next one they are folded.
Running to Stand Still - S1-E6
Continuity mistake: When Lynette is talking to Jordana the items on the table keep changing position in between shots. (00:29:30)
Getting Married Today - S3-E23
Continuity mistake: Gabby's hair in the beginning has her bun high on her head and her tiara is visible from the front. When Bree walks in, and when she overhears Victor and his father talking, her tiara is farther back on her head and no longer visible from the front.
Continuity mistake: When Andrew is talking to his mum, Bree, on his bed, we see him put the magazine down, yet in a later shot it is no longer there. (00:38:10)
Running to Stand Still - S1-E6
Continuity mistake: In one shot during the poker scene the baby moniter changes position to the other side of Lynette then back again. (00:13:30)
Continuity mistake: In the restaurant, Bree makes a salad for Rex at the salad bar. It is fairly tall with lots of tomatoes. The salad she gives him is flatter and missing many of the tomatoes.
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)
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.