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)
Visible crew/equipment: After Alice trips on the Chinese checkers, when Mike gathers the kids in the family room to update them, the shadow of the moving boom mic is visible at the top right corner of the screen. (00:02:50)
Audio problem: When Carol calls and Mike answers the phone, (after Cindy runs and then the entire salad (bowl) falls to the floor) you can hear Marcia and Jan arguing in the background, but that exact (said) audio is looped if you listen closely - it is an argument from an earlier script that is repeated about 6 times or so during the length of Mike's phone call from Carol.
Continuity mistake: The amount and position of the soapsuds on Jan's shirt changes from shot to shot. (00:09:20)
Continuity mistake: When Mike walks into the kitchen asking Alice if he can give her a hand, Alice removes two pots from the stovetop leaving the left side clear, but in the shots from the dining room when Alice trips, there are two large pots on the left side of the stovetop, near the edge of the counter. (00:01:20)
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.