Play It Again, Seymour - April 14, 1953 - S1-E9
Revealing mistake: After Sam nearly falls down the elevator shaft, the scene fades and comes back in with Sam speaking to the landlord about the incident. The landlord brushes off Sam's hat with his hand and hands it to him. The brushing motion was played in reverse first to extend the length of the action.
Play It Again, Seymour - April 14, 1953 - S1-E9
Revealing mistake: Sam opens his left hand when talking to Al at the beginning. His reflection does not. His reflection just points his finger.
Play It Again, Seymour - April 14, 1953 - S1-E9
Revealing mistake: Sam is getting shot at in the aircraft hanger. He hides behind a yellow machine and a bullet hits it. The bullet produces a flash but leaves no mark where it hits. A real bullet would have left a gash at the least.
Play It Again, Seymour - April 14, 1953 - S1-E9
Continuity mistake: The cut on Sam's face from the bullet is larger than the one on his counterpart's face.
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