In the climactic scene in Hugo's hotel room, Pila is standing right behind the seated Gagin with her hand on his shoulder. But whenever we cut to the reverse angle, she is completely out of the shot.
After retrieving the check, when Lucky walks outside it is daylight. He walks a few blocks and the sky is now pitch black.
When Lucky sticks the key to the map, the gum overlaps the side of the map and also sticks out noticeably to the rear. When he retrieves the key later, neither the gum nor the key can be seen, yet the key is still there.
Opening scene at the bus station, Montgomery walks over to the gum machine to insert his coin, but the gum package is already present before he inserts it.
Lucky Gagin introduces Marjorie Lundeen to Pila by her full name even though on their only previous meeting she didn't tell him even her first name.