During the conversation between Lightman and Foster after her upsetting call with her husband, one shot of Lightman has been reversed. The door behind him swaps sides and the parting in his hair changes from the left to the right side of this head. This must have been done in order to preserve his eye line and not "cross the line" because of a different camera angle.
Outside the bus, Walid lets a man get on the bus just before he gets on. Inside the bus a woman is in front of Walid and there is no sign of the man.
Towards the beginning the Afghanistan people are referred to as "Afghanis". The proper term for a native of Afghanistan is Afghan. Afghani is what the currency (money) is called. Afghanis, like dollars, is the plural form.
When Lightman, Foster and Reynolds are investigating the bus bombing, palm trees are visible in the background even though the show takes place in Washington, DC.