When Russell and Claire drive to Leon, they are driving a light blue four door 1974 Chevy Chevelle Malibu that has rectangular tail lights and it is very clean. When they arrive, they are in a light blue four door 1973 Chevy Chevelle with twin round tail lights and the car is filthy.
When Claire and Russel drive to Leon, the position of the white rag at the car window changes several times.
In the opening scene in Chad Asian elephants are used by the rebel troops (instead of African elephants living in that area, who are not especially known for their suitability for domestication) clearly identifiable by their smaller ears and the hair on their forehead.
In the dark room of the guerrilla base the rays of sunlight are cast in two different directions, probably to form an appropriate atmosphere, however it is not possible in natural conditions.
When the convoy in Africa is attacked by a Douglas C-47, it is made to appear it is shooting at the road ahead of it, although the C-47 has no forward-firing weapons. It may have a machine gun in the rear cargo door, but it is in no position to fire ahead of the aircraft.
When Russell and Claire pose for a photo while Alex is on stage at the club after they all first arrive in Nicaragua, the physical picture is from the wrong perspective and distance as it's a freeze frame of the scene taken from the actual movie.
This movie is set in 1979 yet Russell Price is wearing Nike Terra TC running shoes. These shoes were not available until 1981.
At the beginning, when Price is given a lift from the soldiers (Oates is among them), the shadow of the whole crew is cast on the scene.
At roughly 36 minutes, when a plane is bombing streets, allegedly in Nicaragua, a billboard for Carta Blanca can be seen. Carta Blanca is a Mexican beer. The brewery was started in 1980 in Monterrey. it wouldn't have been available when the movie is supposed to take place, and certainly not in Nicaragua.
When meeting Price in Chad, Oates says he's riding with the soldiers to Zambezi. The Zambezi region and river are located in Zambia and Zimbabwe, approximately seven countries and 2000 miles away. There is no reason Chadian rebels would be taking a multi-week drive there.