Another Mother - September 30, 1981 - S2-E13
Continuity mistake: When one of the sicko men from the van pulls a knife on Sam, the white blouse is either tucked into the skirt or hangs over it, depending on the shot.
Glitter Rock - April 12, 1974 - S3-E17
Other mistake: During the album signing at the mall, a woman exposes her breasts to Sam. We see her from the front with Sam's hat covering her breasts. His hat moves just enough that you can tell she is wearing something covering her breasts.
Runaway - July 4, 1964 - S3-E11
Revealing mistake: The family crosses into Colorado from Wyoming and calls out the state names. Wyoming doesn't have Joshua trees, nor anything close to the desert we see. This episode was filmed in Southern California.
Animal Frat - October 19, 1967 - S2-E12
Audio problem: A dog runs by Sam chasing one of the frat pledges. It's barking according to the audio, however the dog does not bark.
Maybe Baby - March 11, 1963 - S2-E20
Factual error: Across the street from the general store where Sam and Bunny escape is an AllState Insurance office. The logo for the store is the more modern 1990s logo. The 1960s AllState logo had a different appearance.
Factual error: Many of the episodes are set in the 1950's or early 1960's, but we always see three-prong electrical outlets in the buildings. Three prong electrical outlets only came into common use in the mid to late 1960's, and were required starting in 1969. While they existed before that, they were only installed in specific use situations.
Pool Hall Blues - September 4, 1954 - S2-E18
Factual error: After Eddie tells his helper to get rid of Sam's/Charlie's pool cue Alberta, we see an exterior street shot with an elevated subway going by, with a lot of 1970s and 1980s cars parked and driving by. Not quite appropriate for the 1954 setting. (00:35:40)
Good Night, Dear Heart - November 9, 1957 - S2-E17
Revealing mistake: When Sam is talking to the sheriff in the parlor and says it can't be prosecuted, he walks in front of a mirror and we see the real doctor in the mirror, except we see the real doctor standing up just as he becomes visible, and Sam's shoulder just to the left. They used the mirror's angle to fake the mirror image, and probably panned the camera over the other actor's head as it swung around which is why he had to stand up. (00:38:40)
Play It Again, Seymour - April 14, 1953 - S1-E9
Continuity mistake: The cut on Sam's face from the bullet is larger than the one on his counterpart's face.
Mirror Image - August 8, 1953 - S5-E22
Other mistake: At the very end of the episode, the last thing to show on the screen are the words "Dr. Sam Becket never returned home." They spelled Beckett wrong.
Jimmy - October 14, 1964 - S2-E8
Revealing mistake: When Sam is helping Frank clean his truck, an old couple passes as they are talking. Watch the shadows on the left side of the frame right before they enter. The shadows pause for a second, and then the couple walks on screen as they are being cued by the director.
Dreams - February 28, 1979 - S4-E8
Character mistake: When Sam is trying to explain to Al how he feels the person he's leapt into, Jack, is still in his head, Sam asks Al if he remembers how their personalities got mixed up when they simul-leaped. Al says he does not. Three episodes previously, in Permanent Wave, Al asks Sam if there's still some of him, Al, left in Sam because of the way Sam is behaving toward the twins. So Al remembers in one episode, but in another, later episode his brain is somehow still swiss-cheesed from the leap on this particular detail. (02:33:40)
The Leap Back - June 15, 1945 - S4-E1
Plot hole: Sam is trapped inside the imaging chamber without a hand-link for the first half of this episode. Yet, somehow, he is still able to follow Al around town. The chamber is only so big. Without the hand-link to recenter himself on Al once he's traveled beyond the walls of the chamber, Sam would have been unable to move much further than the town square he appeared in.
The Curse of Ptah-Hotep - March 2, 1957 - S4-E20
Continuity mistake: The size and shape of the hole Sam creates, when he breaks through the wall, is considerably different on the outside than it is on the inside of the burial chamber. (00:20:10)
The Curse of Ptah-Hotep - March 2, 1957 - S4-E20
Continuity mistake: When he starts swinging the pick-ax, Sam's bandanna instantly moves between shots from around his neck to over his face. (00:19:25)
Goodbye Norma Jean - April 4, 1960 - S5-E18
Factual error: Sam leaps into Marilyn Monroe's chauffeur in April, 1960. But the car he's driving her around in is a 1961 Lincoln Continental convertible. The 1960 had prominent tail fins, the redesigned '61 did not, so the difference is noticeable. This is a model Marilyn could not have purchased until, at the earliest, September of 1960. (00:03:00)
A Portrait for Troian - February 7, 1971 - S2-E11
Continuity mistake: When she's confronting her brother on the dock, Troian's long hair shifts from being completely behind her back to falling over her shoulders in front with each change of camera angle. (00:35:00)
Chosen answer: Per the Quantum leap page at http://www.scifi.com/quantum/episodes/season5.html. 8 August 1953: An enigmatic leap lands Sam in a Pennsylvania tavern, as his own grown self on the day of his birth. As Al and Gushie work frantically to locate him, Sam befriends a wise bartender (popular character actor McGill, who'd appeared in a different role in the very first "leap") and a group of coal miners. As a host of familiar-looking faces pass through the bar - with different identities than Sam remembers - Sam ponders his life of leaping with Al the bartender, who tells Sam he controls his own destiny. Pressed for more, Al the bartender simply shrugs and says, "Sometimes, 'that's the way it is' is the best explanation." Sam realizes he must right at least one more wrong before he can go home, and leaps back to tell Al Calvavicci's wife Beth (from "M.I.A.") to wait for Al, who will survive Vietnam and come home to her. The closing title cards state that Beth and Al have four daughters and will shortly celebrate their 39th wedding anniversary ... and that Sam Beckett never returned home.
Boobra