All Americans - November 6, 1962 - S2-E14
Audio problem: During the speech where Al tells Sam to quit (to force Chewie to play), Sam says he can't quit but his mouth doesn't move for a couple seconds after the words start playing.
Disco Inferno - April 1, 1976 - S2-E2
Factual error: In this episode that takes place in April of 1976, everyone sits around watching an episode of Saturday Night Live with Bill Murray on it. Murray didn't join the cast until 1977.
Catch A Falling Star - May 21, 1979 - S2-E10
Continuity mistake: As Sam is preparing to go on stage as Don Quixote, after catching the lead actor, a quick cut to Dulcinea dancing is shown. It is supposed to be Sam's love interest and ex piano teacher Nicole as Dulcinea. However, you can see Nicole standing in the background, in the pink outfit she was wearing in scenes from the beginning of the episode. (00:41:55)
Good Night, Dear Heart - November 9, 1957 - S2-E17
Factual error: At the end, Sam reads a poem from a Mark Twain book and says, "Twain wrote it when his daughter died." But the poem, famous because it was engraved on the daughter's headstone, isn't by Twain, but by poet Robert Richardson. Twain never claimed authorship, so Sam couldn't be reading it with Twain's byline from any of his books. (00:48:00)
Her Charm - September 26, 1973 - S2-E15
Continuity mistake: After throwing the laundry bags out the back of the truck, close up shots on Sam and the girl show the back of the truck being relatively empty. However, the next shot from the rear of the truck has the back full of laundry bags again.
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
Audio problem: When the little girl is dragging her sister across the room to get her to meet Sam at the pool, she says, "He's waiting at the pool for you," but her mouth doesn't even come close to mouthing those words.
M.I.A. - April 1, 1969 - S2-E22
Continuity mistake: In the beginning, when dressed in drag, Sam has a cigarette with a long bit of ash on it. He looks at his "reflection" and there is a short bit of ash on the cigarette, then it cuts back to him and there is a short bit of ash.
All Americans - November 6, 1962 - S2-E14
Continuity mistake: When Sam and Ruben are fighting in the locker room they knock over a set of lockers (and only one set) and the door flies open on it. When they roll over the set of lockers the camera cuts and 2 sets of lockers are suddenly knocked down with all locker doors closed.
All Americans - November 6, 1962 - S2-E14
Continuity mistake: In the fight between Sam and Ruben in the locker room, Ruben has a white visor in his hands during the fight which magically disappears during the fight after a camera cut, and Ruben leaves after the coach breaks up the fight, without the visor.
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.
Good Night, Dear Heart - November 9, 1957 - S2-E17
Other mistake: Sam opens Hila's diary to a page. The translated voice-over mentions the 4th of July, America's independence and how she met someone with whom she could fall in love etc... The actual text on the pages mentions only the "Beginning of July" and how "3 bears and a zebra were born in the zoo. "Anton" was there and told her about it. His entire family was there and had a lot of fun." The right-hand page mentions how they had a wonderful day visiting the castle at Chiemsee where they had lunch. (00:21:02)
Disco Inferno - April 1, 1976 - S2-E2
Audio problem: When Sam says "I'd rather be dead," his lips don't move in sync with the words. (00:01:35)
Catch A Falling Star - May 21, 1979 - S2-E10
Character mistake: In the preview for this episode, Charlie has trouble getting his countdown straight. He shouts that Sam is on in 50 seconds, then 47, then 48. In the episode itself, the mistake is corrected with a rather obvious overdub, changing the final number to 43. (00:02:05)
All Americans - November 6, 1962 - S2-E14
Continuity mistake: Chewie is wearing the number 86 jersey in both games. However, when he is sitting out with his supposedly injured knee we see a shot of the number 86 jersey chasing an opponent.
Another Mother - September 30, 1981 - S2-E13
Plot hole: Sam wallops both kidnappers and rescues the son. They then leave the two child molesters unconscious beside their van. No one calls the police or has them arrested, so they're free to kidnap another kid. Sam doesn't leap until after an epilogue in which the loose ends are supposed to be resolved - but this question is left unanswered. It's not excused by a "just because we didn't see it happen doesn't mean it didn't" defense. The viewers shouldn't be left with a dangling plot hole, and one line could have cured this one.
Leaping in Without a Net - November 18, 1958 - S2-E19
Audio problem: In the beginning of the show, when Sam's father tells him to get down, Sam climbs down and falls off the net. When he hits the dirt it makes a sound like he's hitting a board.
Leaping in Without a Net - November 18, 1958 - S2-E19
Continuity mistake: When Sam and his sister are on the trapeze and she does a double and he catches her you can see that the bar she jumped from is not moving behind her. Then when she jumps back to it, it's swinging again.
All Americans - November 6, 1962 - S2-E14
Continuity mistake: In the party after the 1st game when Chewie and Sam are talking about the championship, Chewie pulls up a chair and sits on it backwards with his hands in his lap. After the cut to another camera, his arms are up on the back of the chair.
Maybe Baby - March 11, 1963 - S2-E20
Audio problem: When Sam is looking in the mirror talking to Al, he says, "Would you look at me? I've got a gold tooth." However, the reflection doesn't mouth the first part and doesn't even say the second.
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