Star-Crossed - June 15, 1972 - S1-E3
Revealing mistake: Sam stares at himself in the mirror and takes out his wallet to determine who he's leaped into. But the "reflection" in the mirror lowers the wallet and looks back up before Sam does. (00:05:20)
The Million Dollar Bond Robbery - S3-E3
Revealing mistake: All the Liberty Bonds loaded in the bag of Mr. Ridgeway have the exact same serial number. (00:20:00)
Beauty Rest - S4-E5
Revealing mistake: Kathy Ireland is supposed to be dead but watch carefully and you'll see her chest move when Minnie Driver's doing CPR.