Vindicator power: Blood Trail

This power seems to be messed up. I used it on an individual and it told me they went south. So I go a couple south (on a road with only north and south with no branches off between) and it tells me they went north. I go north, it tells me they went south. I finally decided to try it in a location where I know this person would never go, i.e. the Tribunal Spire. Low and behold it was giving me directions. I went one down from the executioner, it said they went north. I go north and back to the original position, and now it says they went up. I go up and it says they went down, although its impossible they could have been there. When I do it multiple times in one place it gives me the same direction, but if I leave and return to that one place, it will give me a new and seemingly random directly. Thanks.