This isn't the only "finely tuned' riddle. Though I've been pretty fortunate and haven't had to wander around long on most voyages.... One did recently slow me down for at least 10 minutes..
"Grove under the tip of Canon Peak"
Yea, there is a group of trees of a different type than most on the island so we had the appropriate "area"... but where you ended up triggering the event was a tiny space hidden behind one tree, a corner of a rock, and the edge of grassy foliage. We walked all over each area repeatedly... It was dumb luck that one of us ran behind a tree.
Bottom line?
They need to widen the areas of some of these more general locations for the trigger proc. A grove should accommodate the entire grove.. the beach should account for all of the beach... etc.