The Winner - S2-E21
Continuity mistake: When Mike and Carroll drive Bobby to the TV show for the ice cream eating contest they leave in the blue convertible. They return home in the brown station wagon.
Continuity mistake: When Cindy goes downstairs to ask "isn't anyone coming up to say goodnight?" or something similar, when Alice is talking to Mike and Carol about Sam not coming over, Cindy is wearing her pyjamas. She then gets in trouble and goes straight back up to her room and she is suddenly dressed in jeans and a top - her hair has different hair ties in it too.
Revealing mistake: When Peter is on the trampoline, instead of saying "Peter," Carol says, "Go get 'em, Chris!" and a few minutes later the same thing happens after Cindy has a turn alone, you can hear Greg say "Why don't you give it a try, Eve?" (00:18:10 - 00:19:50)
Deliberate mistake: While Bobby's parakeet is flying around downstairs, before the bird settles down on the TV set there are two closeups of Bobby which are flipped shots, note the furniture and Bobby's PJs. (00:07:00)
The Not-So-Ugly Duckling - S2-E9
Continuity mistake: When Jan comes home and tells her parents that Clark didn't notice her at school, she's wearing a white blouse with a floral design and a red ribbon in her hair, but when she gets to her bedroom and accuses Marcia, she's wearing a striped blouse and a light green hair ribbon. Then when Jan talks to Greg she's wearing a green tee shirt and a dark green ribbon, but when she asks permission to go to the store she's back in the striped blouse and light green ribbon.
The Treasure of Sierra Avenue - S2-E7
Visible crew/equipment: The set lights are reflected in Greg's beach ball in what is supposed to be an outdoor scene. (00:20:35)
Lights Out - S2-E20
Revealing mistake: When Peter is on stage at his school for the talent show, Cindy gets into the disappearing lady booth and Peter closes the curtain. He says the magic words, yanks open the curtain and Cindy has disappeared. Look at the top left side of the booth and you can see where the stage curtain is piled up on top of the booth. There is just enough room for Susan Olsen to get out of the booth and then get back in.
Deliberate mistake: When Bobby's at the treehouse the second time for his initiation into the club, there's a boy already up in the treehouse, and after Peter takes the birdcage from Bobby's hand, the next closeup of the boy in the treehouse is a flipped shot, note the wood boards. (00:08:25)
Confessions, Confessions - S2-E12
Visible crew/equipment: During dinner, when the freshly glued vase with the flowers springs a few leaks we can see the top of the kitchen set in some shots, particularly when Alice makes the joke about three coins for the fountain.
Confessions, Confessions - S2-E12
Continuity mistake: When the vase gets broken, it's easy to see that one large piece flies off the chest of drawers onto the floor. And when the boys look down at the broken vase from upstairs, three pieces are on top of the chest of drawers. But Greg - seen later trying to fix it - says something to the effect of "Good thing it only broke into three pieces." So what about the piece that flew off onto the floor? (00:02:00)
Alice's September Song - S2-E23
Revealing mistake: One of the times that Sam comes over to visit Mr. Brady, he comes in through the back sliding "glass" door. There is no glass in the door. You can tell this because when Sam closes the door, to do so, he puts his hand through the areas where glass would be.
The Un-Underground Movie - S2-E4
Continuity mistake: During the filming of Greg's movie, Mike is in the stockade when Peter dumps the box of "snow". When the family sits to watch the film, Mike is released from the stockade by Carol before the snow is dumped. (00:17:45 - 00:20:10)
Continuity mistake: Cindy's notebooks keep changing in number and color during Peter's confrontation with Buddy. (00:21:30)
Confessions, Confessions - S2-E12
Revealing mistake: At the start of dinner, in the wide shots we can see the table and chairs directly on the carpet. When Carol notices the leaky vase and calls for Alice, in the wide shot as Alice approaches the table, now there's plastic sheeting spread across the carpet under the table, as well some visible tubing under the table, presumably for the water stunt. (00:05:45 - 00:08:15)
The Impractical Joker - S2-E13
Continuity mistake: While Myron is on the closet shelf with Carol's shoes, the camel colored shoes repeatedly change between having camel colored heels to dark brown heels. (00:11:35)
Lights Out - S2-E20
Plot hole: When Alice brings Cindy to the auditorium to help Peter in his magic act, her cape is already there backstage. She was not going to be the assistant until Jan got hurt. (00:22:10)
Confessions, Confessions - S2-E12
Continuity mistake: When the boys are playing ball in the bedroom, Greg has on a pair of dark jeans. When they go downstairs to see the broken vase, he is wearing a normal pair of blue jeans. (00:01:30 - 00:02:30)
Continuity mistake: The number and position of the darts on the dartboard changes between shots. (00:06:45)
Continuity mistake: Through the course of the episode, Greg has a spot in his eyebrow over his right eye that switches from shaven to unshaven.
Continuity mistake: The horse figurine and telephone on the table next to Greg are not in the same positions from shot to shot. (00:07:15)
Answer: Much trivia has been written about "The Brady Bunch, " including the various interrelationships and dynamics among the members of the cast. For example, much has been written about why Robert Reed's Mike Brady did not appear in a couple of episodes, including the series finale, due to rancorous creative and artistic differences with series creator, Sherwood Schwartz. However, in contrast, I have never run across any reasons given why a particular child did not appear in specific episodes - only that the episodes were missed. This suggests the causes were likely unexceptional, such as illness, injuries, vacations, or real-life family obligations.
Michael Albert
Although those options ARE possible reasons, it just seems a bit ironic that this happened all in Season 2 ONLY and within a short amount of nearly consecutive episodes. Never happened during the other 5 years of the show at all.