The first time Anne approaches Bob's car, she does so twice.
When bob and Anne arrive at Bob's place the first time, the vehicle behind Bob's car changes from a car to a truck.
McKimmie demonstrates the four-dial combination-lock for the gang by turning all four dials before opening and closing it. But when Roger practices his safe-cracking technique on it, he misses the upper-right dial and instead works the lower-right dial a second time (after sandpapering his fingertips).
When Bob goes to ask for money to the race horse owner, you can clearly see the shadow of the camera on the ground.