Revealing mistake: During Jack's dance scene, the old lady that he dances with spins away from him and knocks off a man's toupee. The actress was supposed to knock it off as she went by, but it's obvious that she misses and instead quickly reaches over to snatch it off his head instead.
The Not-So-Great Imposter - S5-E9
Revealing mistake: In Angelino's kitchen, when Mr. Angelino comes in and mentions steaks for eight people are needed, look behind him at the door's window. Janet is briefly seen watching (as if waiting for her cue to enter), then quickly ducks out of sight. A second later, she's seen again while Angelino asks Felipe to help him in the freezer. She then runs in the door with Furley as if they first arrived at that moment.
Revealing mistake: In the episode "Out on a Limb", Jack leaves Terri in Mr. Townsend's office lobby to keep the secretary busy while Jack is supposed to climb a tree outside up to the window and move from window-to-window to get to Townsend's office. If you look at the window behind Terri and the secretary, you'll see Jack magically walk through the brick wall to get set up for the tree climbing scene.
Diamond Jack - S7-E3
Revealing mistake: As Terri exits Jack's bedroom to stall the diamond thieves, you can momentarily see into the girls' bedroom. The wall that should be between the girls' bedroom and Jack's bedroom is missing and the floor and blue curtains of Jack's bedroom set are visible. Someone's arm wearing a light colored shirt (John Ritter's sleeve is brown and Joyce DeWitt's sleeve is black) can also be seen moving. (00:25:00)
Revealing mistake: At the end where Janet and Jack are in the bathroom (off camera, as he is confessing why he took the car), - you can plainly see that the door to the bathroom is a breakaway door compared to the other episodes, - and even in that particular episode. It's changed in the middle of the episode.
The Not-So-Great Imposter - S5-E9
Revealing mistake: The kitchen of the husband with the cheating wife is the same kitchen used for Chrissy's parents house in Fresno at the very end of the next episode end of episode "Jack's Other Mother" (S05E10).
Revealing mistake: When Jack and Janet are in the entry looking around for burglars, their voices are over-amplified, indicating they are in a sound studio.
Jack in the Flower Shop - S2-E19
Revealing mistake: Once Jack arrives home from his first day, Janet follows shortly behind him with her arms full of groceries. She hands the bag to Chrissy but watch at the bottom of the bag - it starts to come apart and Chrissy grabs the bottom of it and holds it together. The end sight gag is that when Jack storms out, and Janet storms off, Chrissy then goes to go to the kitchen, and the groceries fall out of the bag at the bottom - but it's because then she's holding the bag then around the center.
Revealing mistake: The lights around the stage reflect in Jim Walsh's sunglasses a few times.
Revealing mistake: Studio lighting on Janet and Chrissy's tent at night, in the middle of the woods. (00:21:12)
Revealing mistake: After Chrissy purposely spills the wine onto her married date's lap, he raises the glass, and it's cleverly covered in saran wrap, so that the glass pieces don't go flying when she breaks it with hers.
Revealing mistake: Any time a main house light or a lamp is switched off, it is still bright from the studio lights.
Revealing mistake: When Chloe (the new hire) and Janet are talking on the couch near the end, water spots suddenly appear on Chloe's shirt, indicating the actress was lactating while filming.
Suggested correction: Just because it was never mentioned in the storyline of the show, there is no reason Chloe couldn't have a baby at home thus causing the lactating.
Sorry, but the wording in this correction is confusing. Agreed, there was no mention in the show of Chloe having any baby at home. So very well, she may have been lactating, which explains the sudden water spots as mentioned.
