When Rachel goes riding bareback and first sees the old soldier, the cinch holding a saddle on is clearly visible as she sits on the horse talking.
When Ben goes out with his brother Cash to find Abe Kelsey, he is not wearing neckerchief. Later in the country, when he dismounts, he is using a neckerchief.
When the piano is delivered, Mrs. Zachary sits down to play it, and it is in perfect tune. Not possible! Moving a piano always knocks it out of tune, and moving a piano in a wagon across that terrain would have made it terribly out of tune.
When a Kiowa break into the sod house from the roof, Ben takes his pipe tomahawk from him and clearly hits him with the broadside of the ax instead of with the ax blade.
Several scenes with a blue NIGHT time sky. Obviously filmed in daylight with a filter to darken the scenes.
In the closeup scenes of Rachel, her false eyelashes are quite obvious.
In the scene where the piano is delivered, Lancaster's hair style changes again and again, from trimmed to long, from wind swept to coiffured.
In the search scene in the desert, at high winds, when the two cowboys try to reach for the cactus' protection, the horse's mane dangles like if there was no wind at all.