I've done quite a few tests with this trying to make sniper scientist NPC's and noticed the NPC will not target players if they are at a higher elevation than the player. You have to be fairly close to the elevation for them to target you. Is there a setting to fix this or could this be something to be worked on for the future? It's only a minor incovenience at this point, nothing serious. 

Did some more testing and it seems to only be working with distance and is effected by the aiming down the sights. If an object would normally get in the way of the view down the sights, the NPC's won't fire, even when the player is in view of the NPC. It also seems to be affected by what terrain the player is on? My distance and elevation is the same but as soon as I am on the bridge  (with same elevation) the NPC stops firing. Maybe the placement is just throwing the NPC off slightly.