There's Something About a War - S2-E13
Continuity mistake: When Lynette and Tom are talking, Tom says "Really I got the job?" and puts down the newspaper he was just reading. In the next shot we see Lynette and you can see Tom is still holding the paper and puts it down again.
Like It Was - S3-E4
Continuity mistake: When Gabby and Carlos are driving in the car, Gabby's hair keeps switching from behind her ear when the shot changes.
Revealing mistake: Baby Lily is supposed to be a newborn, but she must be like 4 or 5 months old. When she is supposed to be tucked in a blanket, it's very obvious that they're using a doll that is much smaller than the actual baby.
Audio problem: When Susan suspects someone might be in the house, the seduction music she has put on for Mike is drowned out by the score. When she accidentally hits Mike across the face, the score stops, but the music that was playing in the background has gone. The song in the background before now was music within the show, and it was loud enough to be heard around the house, so we should still be able to hear it.
If There's Anything I Can't Stand - S4-E4
Continuity mistake: The amount of cream on Victor's chest during his rubdown changes between shots.
Continuity mistake: When Gabrielle and Carlos are saying hello to Ashley, the position of her hands change on the ball, from the front to the side to the front again. (00:14:40)
Deliberate mistake: In the episode where Mary-Alice Young's house is open for buyer's inspection, the phone number on the "For Sale" sign has been digitally blurred.
Love Is in the Air (a.k.a. What I Did for Love) - S1-E14
Factual error: Lynette's neighbor tells her that the pot Lynette's sons gave her is really hers, the neighbor's, and she bought it in Costa Rica. She turns the pot over to show Lynette that the price is marked on the bottom, with a number followed by the letter p. One supposes that the p might stand for peso, except that the currency of Costa Rica is the colon, which consists of 100 centavos. No p in sight.
Character mistake: When Bree calls the police when she hears a noise downstairs, she says she lives at 4355 Wisteria Lane when her address is in fact 4354 Wisteria Lane. 4355 is the Scavo residence, not the Van De Kamp residence.
Continuity mistake: Series 3 Episode 1: When Bree welcomes Carolyn to the engagement party, she is holding a tray in her hands, but when Carolyn starts telling her about Orson's past, the tray is gone.
Continuity mistake: When Bree goes to see Zak, in one shot her hands are intercrossed, then in the next her arms are crossed. (00:17:55)
Continuity mistake: On the note Mary Alice receives that leads to her suicide, the position of the three sentences changes throughout the series. In episode 1.1 (Pilot), all three lines are written on the top half of the note (above the crease), but in later episodes the first two lines are on the top and the third is on the lower half. The left margin also gets smaller, and the handwriting varies slightly.
Continuity mistake: When Betty is shown the crime scene photo of Melanie's body, Melanie is inches away from a pallet and the jacket covers most of her torso leaving only the right arm exposed. In the flashback scene, Melanie is feet away from the pallet and the jacket mainly covers her chest and face, leaving both arms uncovered.
There's Something About a War - S2-E13
Continuity mistake: As the nurse is talking to Susan about the operation, the folding of the paper the nurse is holding on the clipboard changes between shots. First it is half folded over, the next shot it has been folded right over and is being held right down. After this shot it changes again and is now folded back without her moving the paper.
It Wasn't Meant to Happen - S2-E20
Continuity mistake: When Gabrielle goes over to Dale to get him to sign the custody form for the baby; the sheet of paper is all creased and folded up. But when she shows it to Carlos it is not creased at all.
Continuity mistake: When Lynette and Gabrielle are talking to Paul, the boxes Gabrielle are holding change position between shots under her arms. (00:34:30)
Now I Know, Don't Be Scared - S4-E6
Continuity mistake: When Carlos walks in to talk to Gabby about staying with Victor, she is drinking a glass of wine. She drains the glass except for a small sip, when she puts the glass down it's half full.
Continuity mistake: When Bree Van De Kamp is first shown with her muffins, we see that the hand towel on the right basket is not in her hand, then when the shot changes it is. (00:05:20)
Continuity mistake: When we see Lynette driving her kids, in the first shot we see some red, blue and white decoration in the front of the car to the right, then when the shot changes it's in the centre. (00:13:50)
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.