When the Brady's house is shown from the outside, the half-second floor is shown on the left. However, from the inside, the half-second floor is clearly on the right.
When Cindy says she has to burp her doll, the doll is sitting next to her on the bed. In the next shot, the doll is in Cindy's arms, she just putting it down.
After Carol and Mike tell each other they weren't "harried and hopeless," Mike says they'll tell the kids after their TV show. At this time, Mike is wearing a red sweater and Carol is in a blue dress.
When they are watching TV, Mike is in a suit (minus the jacket) and Carol is in a skirt and brown sweater.
When Mike shows Alice the newspaper with the Dear Libby column that contains the letter from Harried and Hopeless, he says that the newspaper is yesterday's edition. However, the events that happen from the time that Marcia first reads the letter from Harried and Hopeless in that edition to the time Mike makes that statement would have been at least two days, and not just one.
A worried Alice writes a letter to Dear Libby wondering about the previously run letter in her column. However, both Carol and Mike had shown Alice the letter in the paper, so she should know neither wrote it. If one of them had written the letter, that person wouldn't have asked Alice about it, wondering if the other wrote it.
When Marcia first reads the Dear Libby letters to Jan and Cindy, Jan asks Marcia to read the next letter, which is the one before the letter from Harried and Hopeless. By logic, the Harried and Hopeless letter would be at least the third one in the column. Later, when Carol and Mike individually show the column to Alice, they both say the letter from Harried and Hopeless is the second one in the column.