Continuity mistake: When Greg and Marcia are taping the fake message for Peter, Greg says, "Bang, he buckles down and brings home an A." But when Peter listens to the message a minute later (16:15), Greg's statement is now "Bang, he brings home an A." (00:14:50)
Continuity mistake: The microphone next to the tape recorder moves from one shot to the next. (00:26:05)
Audio problem: When Peter is hinting to Carol that he is still growing, the audio changes to being dubbed in from Peter separate from the actual scene after Peter stands up and mentions he wants cowboy boots. Then the audio is back to normal once Peter mentions "Brown" cowboy boots.
Factual error: About 1/3 through the show, Greg has to talk to Marcia and asks Peter to leave. On the way out Peter stops to start recording on the tape recorder. He only pushes the play button. He would have had to push the red record and play button to record their conversation.
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.