Trivia: Barry Williams has a Band-Aid on his lip in this episode because he was in a car accident a few days before filming and needed stitches in his lip. (00:05:00)
Trivia: Frank Delfino - who plays one of the Kaplutians in Bobby's dream - utters the line "One small step for spacemen, one giant step for Kaplutians." The line was an ad-lib. (00:14:05)
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.