Other mistake: Major Turner tells Reacher that the men Parasource killed were shot twice in the back of the head. During Prudhomme's telling the images show the downed soldier on his back. The other is shown being shot and falling on her back. Then the two kill shots each. They couldn't have been in the back of their heads.
Other mistake: When the soldier says "Sir, she is trying to access the system" we can see the name she is typing in as she is typing it. This isn't possible unless they have a remote desktop connection, which they don't because they don't know where they are at. They are also using MacOS with a Windows background which isn't impossible but it is kind of weird. (00:29:15)
Other mistake: After Reacher and Turner rescue Jack's daughter, prior to flying to New Orleans, they take her to eat at Ted's Frosttop Diner...which is in New Orleans.
Other mistake: At the end when Reacher stops by to say goodbye to the major she alights from a cab wearing an oak leaf on her beret (a Major's insignia) but only 2 stripes on her uniform sleeve... those of a Captain, not the 2 1/2 of a Major.
Answer: Although it's technically a mistake, it is common in films to show military officers in dress uniforms with medals and ribbons to show that particular soldiers are important. A layperson may not know military uniform protocols but they can certainly tell that dress uniforms with a lot of medals signifies high rank at a glance.