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