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)
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
Continuity mistake: The wide shot of the raft shows clear skies but the closeups are all cloudy.
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