Quest “Bring the Thunder” is bugged for me. None of the interactable objects spawn for me making the quest incompletable.
Tried abandoning, relogging, leaving the continent and every combination i could think of but the problem still persists for almost two hours and i cant progress the main story.
Having same issue. I found just running around spamming the buttons I was able to get random placements… very annoying but can at least progress.
Your actionbar gets changed. Try that and see if that solves it for you. 
I had same issue, accepting the quest while not mounted fixed it for me. Think the skyriding action bar was causing the issue.
Go to where the arrows end, stand between the arrows, and gently move your cursor around until the little hand changes colors. You’ll be able to drop them. Once I was able to drop the first one, I had a MUCH easier time placing the rest. Be patient, watch the hand change color, and click when it’s the non-common color and ignore the decal / ring. Once your cursor is the right color and you click, it works.
Why does this seem to always be the answer when I can’t figure out what is going on… Thank you traveller!
Any time.