The Great Earring Caper - S4-E20
Continuity mistake: During the kids' ping pong game in the backyard, there is something white near Jan's feet that appears to be a spare ball. But in the very next shot, it's gone. (00:12:40)
The Great Earring Caper - S4-E20
Visible crew/equipment: The stage lights are reflected in Peter's magnifying glass. (00:04:00)
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.