A Song for the Soul - April 7, 1963 - S4-E15
Revealing mistake: When Al jumps into the shot out of nowhere on the steps after the record producer leaves, Sam and the two girls abruptly move, giving away the technique to achieve Al showing up. The transition is usually smoother, this one happens to be rough and noticeable.
It's A Wonderful Leap - May 10, 1958 - S4-E18
Continuity mistake: When Sam goes in to talk with Max's father, Sam/Max is wearing glasses. But in one brief shot, his reflection in the mirror isn't. (00:20:05)
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)
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)
Lee Harvey Oswald (1) - October 5, 1957 - November 22, 1963 - S5-E1
Continuity mistake: In the Japanese bar, when Sam takes a drink from the beer bottle, the label is facing him. When Oswald (who is Sam's reflection in the mirror) takes the same drink, the label has rotated several degrees and is facing outward, away from him. (00:28:15)
Leaping of the Shrew - September 27, 1956 - S5-E3
Factual error: On the island, Vanessa sees Venus in the sky and it looks very dark. The other shots show the sun is still up so the Venus sighting wouldn't look like that.
Leaping of the Shrew - September 27, 1956 - S5-E3
Continuity mistake: The wide shot of the raft shows clear skies but the closeups are all cloudy.
Leaping of the Shrew - September 27, 1956 - S5-E3
Revealing mistake: The background while Scott is on the raft with Brooke Shields is blatantly a studio wall. The clouds have streaks on them with dark colors and the seam where the ocean meets the wall can be spotted. The film "The Truman Show" used the same technique.
Nowhere to Run - August 10, 1968 - S5-E4
Factual error: Twice in this episode, characters refer to the Vietnam war being over. But the setting is 1968. The Vietnam war didn't end until 1975. (00:34:20)
Deliver Us From Evil - March 19, 1966 - S5-E7
Revealing mistake: When Ilia is spurned by Sam, she sits on the bed and rips her clothes. When she goes to scratch her face, you can see the fake blood on her hand when she goes to smear it on her face.
A Tale of Two Sweeties - February 25, 1958 - S5-E12
Revealing mistake: Sam's reflection in the mirror near the beginning of the episode drops his handkerchief too quickly after wiping his mouth, making things not match up.
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)
Memphis Melody - July 3, 1954 - S5-E21
Visible crew/equipment: While Sam and Sue Anne are singing Amazing Grace at the diner, right after the shot of the cook starting to play the harmonica, in the next wideshot the actor's T-mark becomes visible on the floor at the bottom, left side of the screen.
Mirror Image - August 8, 1953 - S5-E22
Continuity mistake: When Sam tells Al the bartender that he knows another Al who uses the term "caca," Al leans over toward him to say, "Common expression." The camera angle reverses, and Al is abruptly not leaning any more, but standing back from the bar in his earlier position. (00:16:25)
Mirror Image - August 8, 1953 - S5-E22
Visible crew/equipment: After Sam tells Al the bartender that he wants to talk philosophy, Al tells Sam that he's not just the bartender, he's also the owner, then when Al walks behind the counter the actor's T-mark can be seen on the floor. (00:26:50)
Mirror Image - August 8, 1953 - S5-E22
Audio problem: During Sam's conversation with the bearded Russian miner, each of them plainly mouths the word "stone," but for some reason, the word is both times dubbed over with "slate." (00:33:10)
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.
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