After Orry throws Ashton out of Mont Royal, he goes back to the study to pick up his cane. When he bends down to pick up the cane, his tie is undone. When he stands back up, the tie is tied again.
When Orry breaks up Charles's fight at the tavern, Orry's waking cane bends when he hits one of the fighters on the back.
When Constance and George discuss joining the underground railroad, Constance's white bikini panties are visible through under her nightgown. Women of that era wore pantaloons or nothing at all under their nightclothes.
The celebration of secession was filmed in Washington Park in Charleston, SC. As the union soldiers exit the park, the base of a monolith is visible in the background. It's a monument to historic battles of the Civil War.
At the West Point graduation ceremony, trees in the background are draped in Spanish moss, which does not grow in New York state.