Fighting their way through the bush, Dobbs passes through a section where the branches have been cut by Howard in front. Then around 10 seconds later the shot of Howard actually cutting through that section is shown.
As Dobbs mutters to himself, Curtin walks between Dobbs and the water race. When he gets to Howard and the water tank at the top of the race, Curtin comes in from the other side of the water race, despite there being no crossing point between Dobbs and the tank.
As Dobbs is looking around trying to find Curtin's body so that he may bury it, he runs into some bushes. As the camera pans to follow him you can easily see where the set ends. A clear space with a light and some sort of water truck is plainly visible
When Howard is translating for the Mexican, he claims he is warned that there are tigers that can climb trees with birds in their mouths. However, the Mexican says no such thing, only giving a warning of the rough terrain ahead.
During the gunfight with the bandits, Howard refers to the newcomer as Cody. But at the end of the gunfight, he asks "Wonder who he is?" and uses the newcomer's wallet to identify him as James Cody. However, Cody gives his name to Curtin at the General Store. Curtin briefed the boys when he got back. Howard wondering who he is really means Howard wanting to know more about Cody.
When Curtin arrives in Durango for supplies, the Federales are questioning Gold Hat and a member of his gang. It's implied they are executed, as we here gunshots, and Cody explains to Curtin how the Federales go about their justice. Yet these "executed" men appear later in the film.
Curtin reads Cody's letter out of sequence. He starts on the front page, then opens to the inside pages. He glances momentarily at page #2 on the left, but immediately starts to read page #3 on the right. He then reads page #2 before turning to the back page.
During the gunfight with the bandidos at the gold mine, Dobbs runs out of bullets while firing his rifle. He is shown reloading it just as the shooting stops. With absolutely no sound coming from the film, Dobbs fires the rifle(trigger pulled and hammer falls) but no noise or muzzle blast is shown. Some may call it a misfire, but there is no sound as the hammer falls and Dobbs would have reacted to a misfire. Just another case of bad editing.