During the prologue mission where Aloy has to use the tracking feature to evade the Watchers, everything worked perfectly fine.
After the prologue, tracking Watchers has been hit or miss:
- During the first side mission where a girl is in a tree surrounded by 4 Watchers, I was able to show each of their paths just fine.
- After that point, however, I've only been able to see the path of 1 of the 10-15 Watchers for which I've tried to "Select track", and when I did so, it took about 10 seconds for the track to appear. When I tried to select the track for the others, nothing happened at all, no matter how long I waited. The game clearly thought their tracks were visible, though, since the toggle then read "Deselect track".
- During the first main story mission outside the walls, the dialogue sorta makes it obvious that you're supposed to predict where the boss is going to walk, so once again I hit "Select track", and nothing happened no matter how long I waited or how many times I tried. In this case I found something else interesting: when I dragged the reticle across approximately where the track would have been, I was again given the option to "Deselect track". So the game thinks it's drawing the track and thinks that I'm looking at the track ... there's just no track on the screen.
Is this a known bug?
I reloaded from a save point just before encountering the aforementioned first boss, and this time the track popped up instantly when I asked for it. However, later on in the same battle, after I'd caused the boss to run around a lot and it had finally returned to its standard track, I was unable to get the track to show up again.
As mentioned in the comments, I've also had better luck highlighting tracks from up close. However, after the reload mentioned above, the boss whose track I was able to select so quickly was about 150 feet away!
The problem persisted after turning off my console and restarting the game.