The Leap Home (1) - November 25, 1969 - S3-E1
Factual error: The Post Raisin Bran cereal box sitting on the Beckett family breakfast table in 1969 has a 1990s box design. (00:18:00)
Private Dancer - October 6, 1979 - S3-E14
Factual error: When Sam knocks on Diana's door, she opens it. But we've just been told that she's completely deaf, so there's no way she could have heard him knocking. Though she dances to "vibrations in the air," this is with music played at volumes high enough to cause such vibrations. Sam is absolutely not banging on her door that loudly.
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