Star-Crossed - June 15, 1972 - S1-E3
Revealing mistake: Sam stares at himself in the mirror and takes out his wallet to determine who he's leaped into. But the "reflection" in the mirror lowers the wallet and looks back up before Sam does. (00:05:20)
Good Night, Dear Heart - November 9, 1957 - S2-E17
Revealing mistake: When Sam is putting the locket on her in the coffin, Hilla's "corpse" is breathing. (00:39:00)
Sea Bride - June 3, 1954 - S2-E21
Revealing mistake: At the beginning of the show they go to great pains to show (on more than one occasion) the "reflection" of Sam in the mirror. However, when the girl shoves him against it, kissing and slapping Sam, it is his real reflection.
Revealing mistake: Almost every time Sam looks in a mirror or the viewer sees Sam in a mirror, the movements of Sam and Sam's "reflection" hardly ever match up correctly as if it were Sam's real reflection.
Pool Hall Blues - September 4, 1954 - S2-E18
Revealing mistake: After Al comes back when the power is turned on, Sam wins a game, breaks for the next and then we see a wide angle shot and the noise is made when Al shows Sam where to shoot. But the beam doesn't appear, even though the shot is seen by viewers.
Private Dancer - October 6, 1979 - S3-E14
Revealing mistake: When Sam is studying the sign language textbook and Al pops in, Sam's right hand makes a noticeable jump, though it's supposed to look like a continuous take. (00:20:10)
Double Identity - November 8, 1965 - S1-E6
Revealing mistake: Sam's reflection character turns around too slowly in the mirror at the beginning of the episode.
Revealing mistake: Al is supposed to be a hologram. However, he is constantly casting shadows, and as a projection, he shouldn't.
Another Mother - September 30, 1981 - S2-E13
Revealing mistake: When Sam and Al are in the station wagon pursuing the van, both Sam and Al's reflections are visible on the wagon's front hood. Al, as a hologram, shouldn't have one and Sam's reflection should be as Kevin's mom.
Animal Frat - October 19, 1967 - S2-E12
Revealing mistake: When Sam and Al are walking and talking, just after Scooter (being chased by the dog) throws Sam the dean's prized basketball, Al's shadow is visible on the ground, though as a hologram he doesn't actually have one.
Play It Again, Seymour - April 14, 1953 - S1-E9
Revealing mistake: After Sam nearly falls down the elevator shaft, the scene fades and comes back in with Sam speaking to the landlord about the incident. The landlord brushes off Sam's hat with his hand and hands it to him. The brushing motion was played in reverse first to extend the length of the action.
Piano Man - November 10, 1985 - S3-E15
Revealing mistake: When Sam is driving the truck through the fog/smoke, Al tells Gooshie to center him on Lorraine but Al doesn't jump out. The shot cuts to a front view of the fog. The road noticeably jumps forward because there is a dissolve transition in this shot, even thought its the same angle. It's likely it was done to lengthen the shot.
A Little Miracle - December 24, 1962 - S3-E10
Revealing mistake: The fractal of the star stops at a point just below the top of the frame, when in reality it should keep going. This gives away that the star is superimposed over the shot. Oddly enough, when it starts snowing, the effect looks normal.
A Little Miracle - December 24, 1962 - S3-E10
Revealing mistake: The video image over the building that Al shows Michael Blake is placed incorrectly. The edge of the effect is blatantly visible. This effect is corrected later when Blake asks to see the plaza again and the name is changed.
Play It Again, Seymour - April 14, 1953 - S1-E9
Revealing mistake: Sam opens his left hand when talking to Al at the beginning. His reflection does not. His reflection just points his finger.
Leap of Faith - August 19, 1963 - S3-E3
Revealing mistake: The newspaper Father John holds up has the headline "Youth Hit By Train", but the article text under it talks about Diane Feinstein's election race against John Van de Kamp for California governor in 1990, the year the episode was filmed. Other article texts do not match either. The text under the Bangladesh Flood article talks about Germany's reunification, which also happened in 1990, after the Soviet collapse. The paper is a copy of the Los Angeles Times with the titles and date changed. (00:05:10)
Her Charm - September 26, 1973 - S2-E15
Revealing mistake: When Al is helping Sam find Dana in the forest, his feet keep kicking up or moving the dirt and leaves, which a hologram shouldn't be doing. (00:39:00)
Her Charm - September 26, 1973 - S2-E15
Revealing mistake: When driving to the cabin, the mileage markers on the roadside indicate they are in Los Angeles, nowhere near Boston or Baltimore. (00:20:30)
What Price Gloria? - October 16, 1961 - S2-E4
Revealing mistake: When Sam is getting ready with the other woman, the shoes on the floor do not match in the reflection. Their position is off.
What Price Gloria? - October 16, 1961 - S2-E4
Revealing mistake: Sam and the other woman are staring at their reflections while Sam is getting ready. Notice where the woman with darker hair is standing in relation to Sam. Their mirror images are further apart. The woman with darker hair also has her head tilted to the right slightly. Her mirror image doesn't.
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