When the horse tries to untie the knot to free Drury the knot changes several times. He actually reties it once by mistake.
In the meeting scene, Gordon sits next to, then across from John between shots.
When John Drury rides into town while the trial for Duke is going on, you see John start to dismount twice instead of once.
When Drury is lassoed by the posse, the rope around his chest and arms moves higher and lower between shots.
A horse is shown trying to break free from a slender tree. The tree is visibly held up by a rope placed there to make sure it didn't fall over while the horse was jumping around. The rope disappears when the camera does a closeup of the horse. The rope then again appears when the camera is farther away.