Left Behind - S1-E9
Factual error: Ray, Sara, and Kendra are Left Behind in 1958. However, 10 weeks later Sara and Kendra are playing the board game "The Game of Life." The modern version, as seen, didn't come out until 1960 (previously it was called The Checkered Game of Life and doesn't resemble the modern version).
Other mistake: The Lakota is attacking a small group of white men. One is face down on the ground, and he lifts his head to cut his throat. In the background are two cowboy actors joking and twirling their guns. One drops their gun and picks it back up. (00:20:43)
Revealing mistake: Mr Knight shoots Suzie Boreton - after the muzzle flashes and sounds stop the bolt of his MK14 EBR continues to move back and forth as if it's still firing. (00:30:30)
Palimpsest - S1-E6
Other mistake: During the credits, it lists Gloria Mundy as the actress who played Alison Araya. However, Araya is the actress's real name and Mundy is the character's name.