Revealing mistake: In brother Justin's padded cell, the far wall is obviously a painted backdrop. It even flutters when the orderly and doctor walk in! The only solid part is a couple of feet at the end, that Justin leans up against.
Carnivàle (2003)
1 revealing mistake in season 1 - chronological order
Los Moscos - S2-E1
Factual error: Outside the church headquarters where Norman has his stroke is a board saying 'United Methodist Church'. The UMC didn't come into existence until 1968. It was the Methodist Episcopal Church in the 1930s.
Justin: I'm reminded of the phrase "making a deal with the devil."
Tommy Dolan: Aw, come on. I'm not that bad.
Justin: No. You're not.