This video has a decent explanation of it.
https://www.youtube.com/watch?v=t0_msZSwmEk
Printable View
This video has a decent explanation of it.
https://www.youtube.com/watch?v=t0_msZSwmEk
Not quite IMO… my experience is waymarks stay as long as you do not exit the zone. I have been out of los to a mark, but I can see it on the map so I can get in range that it becomes visible.