Continuity mistake: In the 1st episode there are about 20 pictures behind the writers desk. Next episode... Gone, replaced with a giant bookshelf and a bunch of scripts. The bookshelf was behind the couch in the 1st episode.
Continuity mistake: The whole kitchen is completely different from episode 2 onward till the end of the series. (Episode 2 onward it looks the same except for the outside behind the sliding glass door but the background is also flat. The house(s) and trees are flat, there are also no birds out there making any noise).
Continuity mistake: In "Sick boy and the Sitter" the door to the writers room says "Allen Brady Show WRITING STAFF" in a nice 3D all bold caps type font (except for the 1st "N"). In this episode the door then says "Alan Beady Show STAFF WRITERS" also all caps, not bold, and not 3D type font.
Continuity mistake: Rob, Laura, Buddy and Blacky are in Robs basement, there is no wine bar, or giant boulder, and the steps that come down from upstairs lead straight up to nowhere. Because there's a window to the left beside the steps, rather than how it was when they were buying the house where you could see into the house. And there's a giant gap under the wall behind the pool table. There's also a random door that leads somewhere also behind the pool table. (00:24:47)
Continuity mistake: Buddy poked the punching bag with Mel's face on it. Then later Mel comes in when the delivery service guy comes. Mel's face is aiming towards the wall. His face on the punching bag keeps appearing and disappearing every time we jump cut from the writers and the delivery guy.
Continuity mistake: In a different episode the Alan Brady show writers were on a different floor than Alan Brady and Mel Cooley. Yet in this episode they're on the same floor because we can hear Alan yelling at Mell while Rob is in the writers room where Sally and Buddy, currently furious reading the magazine article. (00:14:37)
Continuity mistake: Donna goes back to the den to get her coat to show Arthur. Laura yells at Rob in the kitchen "Rob! Did you lock her in the Bathroom!?" It's a den in most of the episodes... Turns out in this episode it turns into a bathroom with carpet on the floor. (Supposedly when Laura is yelling at Rob in the kitchen).