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.
Continuity mistake: The last line of Alice's recipe, written on the chalkboard, changes from "3 egg yolk" to "3 egg yolks" and back again. (00:06:15)
Continuity mistake: The football diagram that Greg draws on the chalkboard changes from shot to shot. (00:07:00)
Continuity mistake: In the photo of the football reception, the enlarged photo is not from the original. The receiver's legs are in a different position. (00:22:35 - 00:23:20)
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)
Audio problem: When Greg and Peter were in the family room helping Marcia write a letter to Davy Jones, Peter suggests telling him that he won a $10 million sweepstake. Then as they walk into the kitchen, you hear Greg saying "A $10 million sweepstake" and Peter says "$20 million?" It is clear that he wasn't really talking, because the sound of his voice is very distant, although they were only in the next room.
Plot hole: At the end of the episode, the younger kids are singing the song "Girl" that Davy Jones did a little earlier in the show. The problem is that the song was just recorded and hasn't been released yet, they couldn't possibly know the song. Davy gives Marcia an LP, but it is on the same day the song was recorded, it couldn't be on there either.
The Not-So-Rose-Colored Glasses - S3-E13
Continuity mistake: In the middle of the episode, a boxy gold station wagon is pulling into the Brady driveway, which immediately cuts to a shot of a rounder body style, gold station wagon pulling up to the carport.
Continuity mistake: When Greg runs into the girls' bedroom to rescue Bobby from the window ledge, there's a black stuffed animal sitting in the middle of the bed nearest the door. After Greg pulls Bobby into the room, the stuffed animal is at the head of the bed. (00:03:45)
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.
Dough Re Mi - S3-E16
Plot hole: Greg bought a time spot in the music studio to record a song. He writes a sudden new song for the studio at the last minute and then, next scene, the kids are singing the song in the studio along with background music playing. Where did all the instruments come from and who was playing them? Even if pre-recorded, Greg and the other kids would have just shown up at the studio at their time, and no way they would have been able to get the tracks down in advance to an unknown song like that.
Other mistake: When Jan finds the picture of her Aunt Jenny, we see a close-up of the picture with her hand holding it. She then passes it to Carol - and the same shot of the picture with the hand is shown again. (00:02:10)
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)
The Big Bet - S3-E18
Revealing mistake: When Bobby closes the sliding door behind him, the curtains swing outward and through where glass should be, revealing it to be an empty frame. (00:01:15)
The Power of the Press - S3-E19
Continuity mistake: The book Peter's classmate is holding rotates between shots. (00:10:00)
The Power of the Press - S3-E19
Continuity mistake: The book in Jan's arms keeps moving; first the front is facing outward, then the back, then the front again. (00:13:40)
Audio problem: At the end of the show when Alice is blowing the whistle, the whole family comes to the top of the stairs. Mike says "Alice, it's 6 o'clock in the morning" Watch his mouth. It looks as though he curses and the (curse) word was dubbed out.
Continuity mistake: While they're in the courtroom, when Carol is standing beside Harry Duggan in front of the board, the small red car on the board keeps changing from being straight to slanted, depending on the camera angle.
Answer: The dangling bracelet was used for dramatic purposes - to keep the audience on edge.