Continuity mistake: When Peter comes down to answer the phone, he's wearing a blue shirt. When he hangs up the phone, his shirt color changes to a light red/pink color. Then back to blue again.
Continuity mistake: At the start of the episode, in the exterior shot when Jan and Peter rush through the patio door Jan doesn't have a ribbon in her hair, but in the interior shot suddenly there's a long red yarn ribbon in Jan's hair.
Visible crew/equipment: When Mike and Bobby drive up in the station wagon, just as Mike stops the car, on the left side of the screen we can see the edge of the house set. Instead of the usual wood fence in the yard, there appears to be a directors chair (provided to all cast members) in the dark background. (00:05:35)
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.
Deliberate mistake: During Peter's party, when the girls start to gather around Peter to try and convince him that he's not dull, there's a closeup of Peter that's a flipped shot. Additionally, when everyone runs out for the fire drill, Peter's striped tie is tied very differently - it goes from grey/gold at the top to burgundy at the top.
Visible crew/equipment: In the episode where Alice sprains her ankle, Sam comes over and gives Alice some flowers. He leaves and Mike walks in, and the camera zooms into Alice and you can see two shadows of the boom mic, one on Mike's face and another over Alice. (00:14:00)
Continuity mistake: When Marcia takes her last turn placing a card at the top of the tall house of cards, in the shots facing her she's stressed about accidentally collapsing the cards so she holds back her charm bracelet with her left hand, but in the first shot facing the three boys Marcia's left arm is down at her side and the charm bracelet is dangling at her wrist, right beside the cards. (00:21:00)
Everyone Can't Be George Washington - S4-E12
Continuity mistake: When Jan's in the backyard checking on the cloud and moon set decorations being painted by Marcia and Cindy, there's less "dark and gloomy" paint actually painted on the cloud after Cindy stands up with the smiley moon. (00:06:20)
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)
Snow White and the Seven Bradys - S5-E3
Continuity mistake: During the play, Mike's "Prince Charming" hat disappears and then reappears when he leans over to kiss Carol. (00:22:15)
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.