Dreams - February 28, 1979 - S4-E8
Character mistake: When Sam is trying to explain to Al how he feels the person he's leapt into, Jack, is still in his head, Sam asks Al if he remembers how their personalities got mixed up when they simul-leaped. Al says he does not. Three episodes previously, in Permanent Wave, Al asks Sam if there's still some of him, Al, left in Sam because of the way Sam is behaving toward the twins. So Al remembers in one episode, but in another, later episode his brain is somehow still swiss-cheesed from the leap on this particular detail. (02:33:40)