Hey,
I encountered a bug months ago whilst doing campaign quests on venthyr and now as I was doing them for alt I decided to try it again. So get the campaign to point where you have to do
harvester of envy. Then as you get to guide Temel fly him to the nearest flight point and start flying somewhere (tested with random Revendreth area) as you're flying press the 4 key ability. When you get far enough from the quest it will teleport you back but you are now stuck in air and unable to jump. You can mount up and run in the air where ever you like. This lasts trough going to BG's, dungeons, hearthstone to oribos, getting a friend jump you down to the maw.
Have fun