The Hustler - S5-E21
Revealing mistake: When Mike's boss, his wife and two other guests arrive at the house for a night of pool, the four guests are greeted at the front door, enter the brick entry foyer, and descend the steps into the living room. As the camera pans to capture the guests entering the living room, the obviously unfinished and unbricked end of the entry platform can be seen in the shot.
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.