Is There a Doctor in the House? - S1-E13
Audio problem: When Mike walks into the kitchen and sees the chart with the list of kids on it and what ailments they've had, he comments on one of the ailments, saying "None of the kids have had distemper." However, if you watch his mouth, he appears to have originally said "rabies."
Audio problem: When Marcia comes downstairs before the dance Alan shows her his new braces, and as they both head toward the door we hear the clear sound of shoes walking on a wood floor, even though they're walking on carpet. (00:23:50)
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.
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.