ENTER THE GLAoQ! BAH BAH BUUUMMMMM!!!!!! (sorry, had to)
Q: The rulebook states that a lieutenant or hero must end their movement in the same location to attack each other?
A: Heroes and Lieutenants must declare a move action if in the same location and wish to attack each other, but do not have to move a trail away from their current location during the move action.
This is a direct answer from JR and the Descent designers requested by the players to clarify that insanely ambigious FAQ statement about the rulebook. It is the official word, but since it happened after the FAQ it is not in the FAQ.