Lost Locket, Found Locket - S1-E25
Continuity mistake: Jan puts her bathrobe on, flipping all of her hair behind her back. But in the next shot, some of her hair is over her left shoulder. (00:20:30)
Continuity mistake: In a close-up of Mike's hands as he undoes his seat belt, he isn't wearing his wedding ring but he is in subsequent shots. (00:04:15)
Continuity mistake: The tents are small from the outside, but much larger when seen from the inside. (00:18:25)
Continuity mistake: The bottles of pop on the kitchen table keep changing position from shot to shot. (00:22:55)
To Move or Not to Move - S1-E23
Plot hole: The "unexplained noises" (the strange moaning) heard by Carol and Alice could not be heard so loud and clear from the room they are standing in (like we hear in the show). Greg later admitted the noises were on a tape recorder, which he had to have operated, and since he wasn't in their room, the sound would be lower and from another room in the house. Definitely not like how it appeared to them in the show.
Suggested correction: Greg could have used an extension cord, left the tape recorder in one room and plugged it in to play when he wanted to. That's what I did to my younger sister to make her think a monster lived under her bed; she heard it "breathing" when she was alone in the room.
That partially makes sense. Greg could not control when to start the tape because he has to be in the room to hit play. So the only way this could possibly be correct is if he played the tape before Carol and Alice entered the room, and he recorded it with several minutes of dead air before the noises came on, and left it running the entire time.
Only problem with this theory is, Carol and Alice heard it from at least two different rooms in the house at different times. How could Greg have set up the recorder and played it in advance, before knowing what room they'd be in each time?
Is There a Doctor in the House? - S1-E13
Other mistake: At the end of the episode, when they were looking at the chart they created, and Alice was found to add the measles, you see Mike Brady adding the word "Alice." But the kids and Tiger all had columns, but he is adding her as an extra row, which was for the different illnesses, to suggest that Alice was an illness instead of a person having the illness.
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: The amount of cookies in the cookie jar Bobby is holding increases from one shot to the next. (00:10:20)
Continuity mistake: The amount and position of the soapsuds on Jan's shirt changes from shot to shot. (00:09:20)
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)
To Move or Not to Move - S1-E23
Visible crew/equipment: When Alice and some of the kids are in the den Bobby gets up to turn off the TV, and the shadow of the moving boom mic is visible on the wall behind Peter. (00:14:05)
Continuity mistake: When Mike walks into the kitchen asking Alice if he can give her a hand, Alice removes two pots from the stovetop leaving the left side clear, but in the shots from the dining room when Alice trips, there are two large pots on the left side of the stovetop, near the edge of the counter. (00:01:20)
The Grass is Always Greener - S1-E24
Visible crew/equipment: When Mike returns home with the grocery bags, as he sets them on the table Alice walks over, and the shadow of the moving boom mic is visible on the swing door behind Mike, at the top left side of the screen. (00:11:05)
Visible crew/equipment: While Mike is fiddling with his golf bag the morning after Tiger disappeared, just as Mike tells Bobby there's nothing to worry about because his siblings are checking the neighborhood, the moving shadow of the boom mic is visible in the top right corner of the screen. (00:02:45)
Other mistake: When Mike is talking to Mr. Crawford and the operator asks him to deposit another 10 cents, Mr. Crawford said, 'Did I hear an operator ask for 10 cents?' Only Mike would have heard that recording, not Mr. Crawford (he didn't have the pay phone).
Character mistake: At the end of the episode when all the kids line up to head upstairs, Mike gives instructions to line up according to their size (big to small). If you notice carefully when the kids all line up, Peter stands behind Marcia, yet he is slightly taller than her.
Lost Locket, Found Locket - S1-E25
Continuity mistake: When they are getting ready for the reenactment of the night when Jan lost her locket, Greg is about to eat an apple when the boys walk into their room. When Greg sits down, his apple is mostly finished.
The Voice of Christmas - S1-E12
Revealing mistake: Carol's hair is quite noticeably shorter in an almost 'Twiggy' bob. When in the prior episode 'Vote for Brady' it was past her shoulders, curled into a very fashionable bubble flip. Not that she wouldn't have visited the stylist after the campaign. Just a very noticeable difference.
Suggested correction: The episodes were aired out of order, so this episode did not immediately follow the previous episode in production. Plus, this was a Christmas episode and Carol was preparing to sing in the holiday service, which is just one possible reason why she'd change her hairstyle.