Continuity mistake: Through the course of the episode, Greg has a spot in his eyebrow over his right eye that switches from shaven to unshaven.
Continuity mistake: The horse figurine and telephone on the table next to Greg are not in the same positions from shot to shot. (00:07:15)
You Can't Win 'Em All - S4-E22
Continuity mistake: At the start, when Cindy walks into the kitchen she sets her books down on the counter with the book's binding facing the sink, but in the closeup the book's binding now faces the opposite way, toward the stove. Additionally, the grocery bag which was on the counter right beside Carol, has been moved for the closeup so Carol is in full view, but the bag is now at the very edge of the counter near the stove, which is pretty odd since there's not enough counter there to actually hold the full grocery bag (presumably something else supported the bag off camera). (00:01:30)
Confessions, Confessions - S2-E12
Continuity mistake: The vase broken by the ball is obviously not the same one dropped by Carol at the end of the episode. The first one was thicker and darker. (00:02:15 - 00:24:05)
Top Secret - S5-E19
Continuity mistake: The amount of talcum powder in Bobby's and Oliver's hair increases from one shot to the next. (00:14:35)
You Can't Win 'Em All - S4-E22
Continuity mistake: What appears to be a carton of eggs is sticking out of one of the grocery bags in some shots, but not in others. (00:15:00)
Kitty Karry-All is Missing - S1-E7
Continuity mistake: As Bobby empties his pockets in search of his kazoo, he piles the contents on a nearby table. In a long shot, several of the toys (most noticeably a green plastic paddle) disappear, only to reappear when Cindy is leaving the room. (00:18:10)
Continuity mistake: When Marcia is sitting on the couch talking with Davy, the small beige pillow behind her is either up on the back of the couch or much further down depending on the shot. (00:23:20)
Continuity mistake: The amount of cookies in the cookie jar Bobby is holding increases from one shot to the next. (00:10:20)
Continuity mistake: When Zaccariah steals the last piece of fried chicken off the plate, the plate is left completely clean, yet when Alice goes to get the piece a few seconds later, there's a sizable grease stain on the plate. (00:14:05)
Continuity mistake: The kids are in a circle on the living room floor. They're spaced well apart from each other in some shots but right next to each other in others; in particular Greg and Marcia, and Bobby and Cindy. (00:19:00)
Continuity mistake: The amount and position of the soapsuds on Jan's shirt changes from shot to shot. (00:09:20)
Continuity mistake: When Greg comes home after Jennifer gives him her number, Greg is seen entering the house in the living room. Then a few seconds later he is seen entering the other side of the kitchen.
Continuity mistake: When Alice enters the kitchen you can see the ironing board from the doorway. When she is giving Tiger a bath the Ironing board has moved to the wall that can not be seen from the doorway. (00:01:30 - 00:04:05)
Dough Re Mi - S3-E16
Continuity mistake: During the recording of "Time To Change", Jan's hands are always together when she's shown. But in the shots showing just the boys, look at the right side of the screen and you can see fingers (which have to be Jan's since she's standing beside Peter) moving as if they're drumming on something.
Continuity mistake: Ken Berry and Brooke Bundy are seated at least a couple of feet from each other in the wide shots, but are right beside each other (arms touching) in the close-ups. (00:01:30)
Continuity mistake: The CLOSED sign behind Sam in the butcher shop keeps alternating between being tilted to the left and tilted to the right. (00:14:45)
The Winner - S2-E21
Continuity mistake: Bobby goes on a television show for an ice cream eating contest. The host of the show takes the spoons away from the contestants, then tells the kids to put their hands behind their backs. Before they do so a close-up shot of Bobby shows him holding the spoon. (00:19:45)
Continuity mistake: The home number Mike dials in the men's bathroom to check on the kids, is very different than the home number Carol dials in the ladies restroom. (00:18:30 - 00:18:56)
Continuity mistake: The kids walk into the kitchen complaining about the noise from Jan's tap dancing. Peter reaches up and grabs his paper sack lunch and then in the next shot he says "talk about noise pollution" while grabbing his lunch for a second time. (00:09:07)
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.