Chapter four: Alan Scott is previously seen riding a horse bareback, yet when he arrives at the mine, the horse is saddled.
Chapter nine: MacDonald and Jimmy are prisoners of Lafarge. MacDonald is tied up, Jimmy puts a burr under Lafarge's saddle. MacDonald is shown with his hands free, then is tied up again.
In Chapter 2, when the covered wagon tarp gets caught in the overhanging tree branch it appears much higher up on the tree later in the chapter. Much higher than a covered wagon could reach.
In Chapter 5, the gondola cable cars are constantly moving along the cable, except when someone leaps from one to another.
In Chapter 5, when Alan Scott (George Brent) and the Wolf Man leap from one gondola cable car to another, they appear to fly. Probably trick photography. No leaping or jumping was performed.
Abt 12:10 into Chapter 6, when the Indians on horseback are chasing after Alan Scott, you can hear gun shots being fired at him. All of the Indians are carrying bows. No guns.