Exactly as Riamus was saying.
It confused me the first time I saw it. I was in a house it said I was 1.9 m away from
the satchel. which pointed to a dividing wall between a room an the hallway. So I
broke the wall, once I had no solid block between myself and the satchel, it registered
4 meters below me in a table. so i made a ladder and climbed down and got it.
It should only show one number for distance, but like I posted when on a different floor
and a solid block is blocking line of sight, the calculation is like the 2d distance to 0,0 position
when you can see it it changes to 3 dimensional distance or 0,0,0. because ray trace can rebound
off of the actual collider. Imagine like this, when you are on a different floor, it is giving a distance
to invisible beacon, sort of an x marks the spot, but it is not telling you how deep the treasure is
buried. The treasure hunt works the same way.
The way I first tested it was I strafed to the side until the distance stared to rise again, then
at the corner of the poi strafed and did it again, so I had 2 points of reference, from there I could
pretty much tell which room and floor I had to go to.