If you are priority targeting an enemy unit, and that enemy unit gets evacuated or airlifted out of your vision, your priority target arrow will show exactly where the unit was moved to even if it is not in your vision. I assume this error will occur with airlift as well.
In this replay on turn 6 from my vision my priority target arrow points to exactly the hex that doja evacuated his artillery to. (Hold down the V key to see the priority target arrow)
http://www.battledexgame.com/game.php?game_id=32669
