I reported the same bug. Took me a while to figure out, but it is when you cross the line from one zone to another within the same map that they die. A good example is if you run due west from the WP at Krennak’s Homestead toward the vista in Wayfarer Hills. Right when you get to the far edge of the frozen lake, they will die. Another is if you run due north from the WP at Tequatl (forget the name), they die right as you get to the “East Battery”. Hopefully they will fix this soon, it makes necro MM impossible.