First Stop - S4-E14
Deliberate mistake: When they are counting the yards to Aunt Sally's pecan pralines, they count down 300 yards, 200 yards, 100 yards so fast they would have to have been speeding pretty fast to go hundreds of yards within seconds.
Hollywood Anniversary - S4-E24
Visible crew/equipment: After Lucy rushes out with the newspaper to tell Ethel about all the movie stars coming to the party, when Lucy returns to the suite and closes the door, we can see the arm of a crew member and a board with "DPI" (Desilu Productions Inc) on it, at the bottom right side of the screen, and a bit of equipment at the top right corner. (00:15:00)
Other mistake: In some episode Ethel can play the piano and in others she cant.
Lucy Is Jealous of Girl Singer - S1-E11
Revealing mistake: During the rehearsal for the Jezebel number, the dancer's skirt trim is already partially torn or unattached to make it easier to tear, and it is clear that Ricky purposely steps on the trim to rip it off the skirt.
Other mistake: In the first scene when Ricky staggers down the stairs and on his way to work it's supposedly first thing in the morning but the hands on the Grandfather clock are at 12 Noon/Midnight. (00:00:45)
First Stop - S4-E14
Revealing mistake: When the bed Lucy and Ricky are in moves as a train goes by look real close and you can see the wheels on it to help move it across the set piece.
Suggested correction: Not necessarily an error. My bed frame is on wheels.
The Operetta - S2-E3
Revealing mistake: Near the end when the repossession men are taking away the costumes and scenery, as they are removing Ricky's pants one of the chorus members can be seen waiting backstage for her cue to enter screaming.
Character mistake: Bob Hope mistakenly calls Lucy "honey" when she's dressed as the intrusive hot dog vendor. He was supposed to believe she was a man. (00:12:00)
Continuity mistake: At times Ricky wears his gold wedding band, and other times - especially at the Tropicana - it is missing from his finger.
Suggested correction: So he took it off while performing. I googled images of Desi and Lucy and you can see he wore a wedding band in real life. Therefore, taking it off while filming would have been a deliberate choice. It's only a mistake if the band appears and disappears within a scene.
The Adagio - S1-E12
Visible crew/equipment: Crew member shadow is visible at the foot of Ricky's bed near the end.
Other mistake: When Ricky comes home at 3:00 am, the toggle light switch is in the down position. Ricky places his hand over the switch plate and the room goes dark, but the toggle light switch is still in the same down position.
Character mistake: When Lucy and Harpo are doing the mirror routine, Harpo grabs the horn on his belt with his right hand. For Lucy to create a "reflection", she would need to use her left hand but she uses her right hand.
Revealing mistake: When Fred and Ethel come with parts of their apartment's ceiling on them look closely at Ethel. The piece on her left shoulder falls off revealing what looks like a velcro pad to keep it in place.
Continuity mistake: Here it's said by the Ricardos that Fred and Ethel have been married for 25 years. Problem is in Season 1's episode "The Girls Want To Go To the Nightclub" the Mertzes both say they've been married for 18 years.
Other mistake: Lucy walks out on the balcony and sees Van Johnson sleeping on a lounge chair by the swimming pool. The photographic backdrop shows automobiles, trees, mountains, the Roosevelt hotel and many other buildings of Hollywood but when Lucy goes to the pool and sits on the lounge chair next to Van Johnson, the background is just a plain painted backdrop with no cars, trees, mountains or buildings. This plain backdrop also appears in the episode with Harpo Marx.
Revealing mistake: When Lucy's pinned against the sink by her bread Ethel goes for a saw. If you watch the doorway you can see her shadow where she's being given the saw.
First Stop - S4-E14
Visible crew/equipment: The gang stop at the roadside diner was obviously shot in-studio as the bottom seam is quite visible behind the car, and the backdrop shakes a little when Lucy opens the car door.
The Ricardos Dedicate a Statue - S6-E26
Continuity mistake: When Ricky is angry toward Lucy that Little Ricky's pet dog Fred has not learned to be obedient he threatens to return Fred to the dog pound where he says the Ricardos originally got him. However, in episode "6-12", Little Ricky Gets A Dog" Little Ricky admits to Lucy that he got Fred from one of his playmates whose dog had puppies.
Homecoming - S5-E6
Revealing mistake: In the scene in the Ricardo's kitchen, after Fred enters through the rear entrance the door is left open. Through the doorway one can see at a certain point, not just the NYC real estate in the distance but apparently a blown-up photograph of what "appears" to be a man and woman sitting at a small table in a cafe. However, in a subsequent episode of the same view through the rear door it appears that the exact same background photo shot may actually be, not a man and woman but features on the outside of a building, such as one or more windows.
Audio problem: During various shots in the Ricardo living room one can plainly hear what appears to be the whirring of the camera.
