Earlier in the movie when the truck full of drugs was being taken by the two men who stole the starting mechanism, the driver's door is white. Later, when they are involved in the shootout with the two fake cops, the door is grey as it's being hit by bullets. Later when the truck is being refurbished, the grey door is removed and the white door is being put on.
The Counselor drives a 2011 - present model year Bentley Continental GT Coupe in Moonbeam Silver for the majority of the film, however in two scenes the car is instead a 2003-2011 model year Bentley Continental GT with tinted rear headlights. The car is also finished in Moonbeam Silver, however the new model can easily be distinguished by the smaller outer front headlights, squared off haunches and more acute-angled rear 3/4 windows.
When Malkina retrieves the user name and password to Westray's laptop from the blonde woman, she remarks that the password is "five digits", as shown on the hand written note. When Westray's laptop is stolen on the street, Malkina enters an eight character password.
Westray is reading a newspaper in a hotel lobby. When the Counselor sits down next to him, Westray tosses a fully-opened paper to the Counselor, but the paper is folded in the next shot just before the Counselor goes to pick it up.
When the Counselor is in Amsterdam, the diamond dealer tells him an Asscher cut diamond is a "modern version of the old mine cut." In fact, old mine cuts are early versions of round brilliants (and sometimes look like modern cushions). An Asscher, by contrast, is a step cut, sometimes called a square emerald cut.
Because a large portion of this movie is set in El Paso, Texas, you would expect to see automobiles with Texas, New Mexico and Arizona license plates on them. Many of the vehicles seen from the front have New Mexico plates attached to them. However, license plates are only installed on the rear of vehicles in New Mexico.