Revealing mistake: Near the beginning, Montag puts on the fireproof clothing to use the flamethrower. It's really footage of him later taking off the same equipment played in reverse.
Visible crew/equipment: Near the end when Montag arrives at the Book Peoples' commune, he is greeted and ushered into a house. There's a shot from just inside the building, looking out a window towards Montag and his host as they approach. As the POV shifts a little, a reflection of the camera becomes plainly visible in the window glass.