Deliberate mistake: In this episode Lucy is trying to get Ricky to notice that their anniversary is on Monday the 19th by showing him a large calendar with the 19th circled. However, when they are in California and they celebrate their anniversary and Ricky asks for information to be wired to him, the telegram tells him that their anniversary is on the seventh.
Continuity mistake: In this episode, Lucy goes out on the window ledge. In "Lucy Cries Wolf", the window ledge was very different: the walls were made of dark brick instead of concrete blocks, there was no downspout, and the ledge went into the corner and stopped, no continuation on the other wall.
Visible crew/equipment: After driving all day, the Ricardos and Mertzes stop by a run-down diner that serves only stale cheese sandwiches, then end up there again only to spend the night in their one motel room. While they're all in their beds, the vibration of the nearby train causes the Ricardo's bed to shakily slide towards the Mertzes and then back again. The wire attached to the Ricardo's bed is visible.
Visible crew/equipment: After take one of Ricky's screen test, when the director says to Lucy, "I thought it might add interest to the scene if you could make it go around and around like a lighthouse!", the Ricardo's kitchen cupboards and fridge are visible off stage to the left of the director's head.
Continuity mistake: In Lucy's dream, when Carlota Romero comes to their apartment, Little Ricky is sitting in a highchair with a hat on his head. Although later in the scene, you see his hat fall off, the first close-up shot of Little Ricky shows him without the hat. Then immediately, when you see a wide-shot of the scene, his hat is back on his head again.
Factual error: In the film Lucy and the others make, there is a long sequence of footage played forwards, then "mistakenly" repeated backwards. With the equipment and techniques they were using, this would have required not only making a complete copy of the segment, but also reversing the order of individual frames. Just feeding the film in backwards would have also flipped the image vertically. The result seen would be nearly impossible to produce accidentally.
Revealing mistake: While Lucy is out on the ledge, if you look at the pipe as it runs from above the ledge to below it, the two pieces of pipe don't line up. They are off about the full diameter of the pipe. Also when the pipe pulls out, it's obvious the pipe is on a hinge at the bottom and not really attached to the lower pipe. Later, there is also no stream of water falling from above where the pipe was supposed to be connected as a drain even though it is pouring out.
Continuity mistake: In this episode, the Mertzes buy the Ricardo's old washing machine and say that theirs is old enough to be in the Smithsonian, yet just a few episodes earlier ("Sales Resistance") Fred tells Ethel to come and see her new Handy Dandy washing machine.
Character mistake: After Tropicana nightclub owner Mr. Littlefield replaces Ricky Ricardo with Xavier Valdez, "the Konga King," Lucy, Fred and Ethel try to get Ricky's job back by going to the nightclub in a succession of different wigs and costumes, then leaving when they learn that Ricky is no longer performing there. At one point, Fred and Ethel enter the nightclub, posing as "Mr. And Mrs. Crumley." A disguised Lucy enters one minute later and is outraged to hear that Ricky is no longer there. Ethel then pretends to phone a friend to tell her to not come to the nightclub. Lucy says, "Attagirl, Mrs. Crumley." However, when Ethel had told the maitre d' she had a reservation for "Crumley," Lucy had not yet entered and therefore should not have known that name.
Revealing mistake: Lucy, Fred and Ethel are admiring the celebrity footprints in cement outside Grauman's Chinese Theater in Hollywood. In several scenes, the shadows cast by Lucy, Fred, Ethel and a passerby make it very obvious that what appears to be the theater's ticket office, entrance and front wall are actually just a painted backdrop.
Deliberate mistake: Lucy and Ethel try and hide the new furniture in the kitchen so Ricky won't find out about it. This in turn forces Lucy to run through the Mertz's apartment to retrieve items from her own kitchen when Ricky wants them. This is supposedly done because the furniture blocks the doorway and is wedged in place thus preventing them from using the door. However it is quite clear that there is a lot of room for the furniture to be pushed into the kitchen and not block the door. They say it is wedged on the sink but there is a lot of room on the other side by the cupboards, along the back wall.
Revealing mistake: When Lucy and Ethel go down to the jail house to see Rickey and Fred, there is a scene where Lucy says "I wonder how he (Rickey) kisses" and then she kisses him, then Ethel says the same thing about Fred and leans in for a kiss. Problem is she obviously doesn't get anywhere near his lips to touch them for a kiss, yet makes the kissing sound, turns around and says "hmmm" as if the "kiss" wasn't all that . Of course we all know those two characters did not get along on set anyways .