I’m not sure if this is a bug, glitch, etc.. but theres no loot or achievement for killing the Legendary Wyvern atop the cliffs (using mushroom mastery) in the HoT story step 4: “The Jungle Provides”.
I was also disappointed to discover there was no Juvenile wyvern there to tame… =(
Accessed as I first meet the Itzel scout between the rock faces.
“No valid path to target” – Thief life (Dragonbrand)