Is There a Doctor in the House? - S1-E13
Plot hole: Lots of factors here: The doctors end up with the opposite kids that they were supposed to have... Why didn't they simply switch in the first place rather than go through all the drama? Also, the male doctor admits Alice let him in and most likely Alice would have told him first door on the right (like she's given directions in other episodes) to locate Peter. And the biggest question of all is, what doctor would make a house call and not look for their patient rather than just ending up with someone else they were not called to see (remember, each parent called their own doctor to see their biological kid).
Suggested correction: The lady doctor goes to see Peter as Mrs. Brady directs her to Peter's room first. Alice likely knows Peter already has a doctor looking after him, as it can be assumed Carol told her, so she sends the male doctor to Jan's room likely explaining to him that Mike's new daughter is also sick and needs to be checked. As to why they didn't solve this doctor problem to begin with; simply they are still a new family and didn't yet think about this as this is the first time the kids are sick.
Trivia: Florance Henderson's hair style on the show was done on purpose. Few knew that since the 1950's she lost all hearing in both ears. The left hearing came back, but she had a hearing aid over her right ear.
Suggested correction: In the episode "A Fistful of Reasons" from Season 2, her hair was short and her ears fully showed (unless the hearing aid was so small it was BEHIND her ears).
Other mistake: When the boys are playing football in the backyard, watch Greg's right foot - at one point he slips on the Astroturf lawn, causing it to wrinkle and exposing a seam on the "grass" lawn. (00:03:20)
Suggested correction: At no time in the show did they affirm the grass in the backyard is real. Many houses, particularly out west where the show takes place, have artificial grass as it's often easier than caring for real grass which tends to dry up easily out west or not grow at all in some areas. Even in A Very Brady Renovation they made sure to use artificial grass for the backyard.
The grass is supposed to be real. There are several episodes where they are mowing the lawn.
But the renovation show was in 2019. In the early 70s artificial grass was only starting to be adopted in sports stadiums. Not used in homes until many years later.
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?
The Dropout - S2-E1
Character mistake: When Greg was in his room talking to his parents, he said that Joe DiMaggio, Mickey Mantle and Yogi Berra never went to college. Joe DiMaggio attended Yale University, Mickey Mantle attended the University of Oklahoma and Yogi Berra attended Montclair State University.
Suggested correction: DiMaggio dropped out of high school and worked odd jobs before playing semi-pro ball. His son, Joe DiMaggio Jr attended Yale for one year. Mantle was offered a scholarship to Oklahoma to play football, but he never went. He started playing semi-pro ball at the age of 17. Berra dropped out of school after the 8th grade and then signed with the Yankees when he was 18 (but served in the military before playing). Montclair State University gave Berra an honorary degree in 1996.
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.