Every Day a Little Death - S1-E12
Continuity mistake: When Gabrielle is eating fried chicken on the walkway, the bucket she is eating from mysteriously turns between shots.
Continuity mistake: When Bree, Susan and Lynette are scrubbing the road, a red sports car zooms past them. Lynette stands, hurls abuse and throws her scrubbing brush at the car which can be seen bouncing off the car and down the road. She then kneels down and continues to scrub with the brush.
Visible crew/equipment: When Bree is watering the flowers in the bathroom at the hospital, a shadow of the cameraman is visible behind her.
Continuity mistake: When Bree is speaking to Lynette on the phone, Lynette asks Bree if she could borrow her scarf to wear at the job interview. But when we see Lynette at the interview, she has no scarf.
Continuity mistake: When Bree and Phyllis are talking about the funeral, the door behind the Reverend changes from open to closed between shots.
Running to Stand Still - S1-E6
Continuity mistake: When Bree goes over to talk to Dr. Goldfine in the restaurant, she puts her napkin on top of her plate, but when she sits back down, she takes it off of her chair.
Continuity mistake: In the scene where Carolyn shoots Lynette, Lynette is wearing high heels when she is originally shot. But when Lynette falls into Art's arms, she is wearing shoes without heels.
Continuity mistake: When Bree throws a glass of water of Orson to wake him up, the upper part of his shirt goes from being spotted with water to being soaked.
Continuity mistake: When Bree gets out of the golf cart to see Rex on the field, she is carrying a pot of urine in her left hand, but in the next shot, of her upper torso and face, her left hand is clutching the strap of her handbag and the pot is now in her right hand.
Continuity mistake: Season 2, Episode 17: "Could I Leave You?" - When Mr. Beale throws a pencil into his mug, the pencil can be seen on his desk in the shot immediately afterwards.
Continuity mistake: While Betty Applewhite is talking to Bree about her son Caleb, the amount of wine in Bree's glass changes constantly throughout the scene without her ever touching the glass.
It Takes Two - S3-E2
Continuity mistake: While preparing for Bree's wedding, Susan is seen wearing full hair curlers for the entire day, yet on the day of the wedding, her hair is straight without a single curl.
Rose's Turn - S5-E20
Other mistake: Carlos carries Lynette to bed when she passes out after falling in the shower. She was obviously very wet all over when it happened, and is still wet afterward, however, his suit is completely dry.
You Could Drive a Person Crazy - S2-E2
Continuity mistake: When Gabby first goes to visit Carlos in prison, they sit down at a table. Watch Gabby's arms. At one point, she folds her arms, yet in the next shot they are on the table. In the next shot they are folded, and in the one after that they are back on the table.
Continuity mistake: As Susan tries to get the dog to help the second time you can see the towel Susan tried to use to get the dog to help her. The shot then shows Susan and the towel has disappeared. After a quick shot of the dog it cuts back to Susan and the towel has reappeared.
Continuity mistake: When Susan and Mrs.Huber are together in the Supermarket the position of the egg box keeps changing in between shots on the conveyor belt. (00:18:00)
Sweetheart, I Have to Confess - S3-E6
Audio problem: Right after Nora kisses Tom when she says "hey, lets have some more wine.", her lips don't match the words.
You Can't Judge a Book by Its Cover - S4-E7
Continuity mistake: When Lynette opens the trunk of her sister's car, the trunk can actually be seen opening twice.
Continuity mistake: When Lynette asks Jane to not steal Tom from her, the door behind Lynette goes from being open ajar to fully closed between shots.
Bargaining - S5-E21
Continuity mistake: When Juanita rushes down the stairs and goes outside the door, you can see that Gaby is holding a plate of leftover food in her left hand, but in the next shot the plate has suddenly changed into a bowl.
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.