Continuity mistake: The step up into the kitchen is no longer there in later shows such as "The Fur Coat" and others.
The Séance - S1-E7
Continuity mistake: After Lucy tells Mr. Merriweather that he's invited to the seance, when it cuts to Lucy unfolding the card table legs, note the couch behind her with one normal seat cushion on the left, but in the next wideshot there's an additional shorter cushion under the normal cushion. The small towel also repositions itself neatly on the couch. (00:11:55)
Lucy Is Jealous of Girl Singer - S1-E11
Continuity mistake: When Ethel walks in while Lucy's vacuuming, Ethel has the folded newspaper under her arm and there's only small print on the paper, but after Lucy offers Ethel a cup of coffee now the headline can be seen on the still folded paper under Ethel's arm. Then, when Lucy unfolds the paper we see both the front and back page filled with pictures and the headline, but that area of small print which was seen in the earlier shots does not exist on either side. (00:00:40)
Continuity mistake: When Lucy crawls into the New Neighbors' apartment she's startled by the stuffed bear head, and in the closeup of the bear head it's in front of a bare wall, but in the rest of the shots it's in front of furniture. Additionally, other things change as well between shots: the books under the bear, the hat, etc. (00:10:15)
Continuity mistake: After spending the night at the hotel, when Ricky goes to the front desk to speak with the "Justice of the Peace" it's 7:30 on the wall clock. Then, when Mr. Willoughby stands by the stairs and calls to his wife it's almost 7:40, but when Ricky gets ready to propose it's 7:30, but it's 7:45 when Mrs. Willoughby comes downstairs in the closeup, then back to 7:30 in the wideshot. (00:17:40)
Answer: According to Snopes.com, there is no definitive answer, but the mid-1960s is the most verifiable date with "The Munsters" being cited as the first, although others claim "The Brady Bunch" showed the first couple seen in a double bed. An early TV show from the late 1940s titled, "Mary Kay and Johnny" is also thought to have shown the married couple's bedroom as having a double bed, although probably not with them in it. However, this was when TV was aired live, and there are no surviving episodes, only anecdotal accounts.
raywest ★
Something that is funny is that in the movie "A Christmas Story," they show the parents having two twin beds in their bedroom. In a real situation, they should have shown them having a double bed. Lucy and Ricky had twin beds pushed together in an early episode, which would have been pushing television boundaries in that time.