Before going onto the yard, Bogart's hair is dark. When on the yard, suddenly he becomes a blonde.
As O'Brien walks in to inspect the prisoners' cells, some pictures on the walls change or disappear.
A guard drops his lever action rifle from on top of the wall. Rogers goes to it and picks it up. He then shoots a guard from top of the wall, then works the action. Moments later, the Captain approaches Rogers. Rogers points the rifle at the Captain and cocks the hammer. But the rifle would have already been cocked from when Rogers had worked the action of the rifle earlier. Working the action of a lever action rifle accomplishes three things, it ejects the spent cartridge shell, loads a new cartridge into the chamber, and cocks the hammer.
While in O'Brien's office, a pack of cigarettes appears in Bogart's shirt pocket briefly then disappears.
Ann Sheridan's character is credited as "May," but her club poster has her name spelled "Mae." (It is possible the poster was meant to have a fancier spelling since it is her stage name.)
During a tracking shot in the machine shop, the shadow of the camera can be seen against the side of one of the machines as it moves.
Shadow of the boom microphone can be seen moving up the row of men to the left during their lineup at the beginning of the film.
MacLane walks beneath the shadow of a microphone boom as he walks away from his car at the construction site.