This is being hotfixed now. Thanks for letting us know! I'll edit my message once it's fixed :)
Edit: This is related to fletching darts on the island and then getting hoofed off rather than the d'hide set itself. Spoke to the player in game and the developers. Going to make it so we can allow players to fletch darts for that specific clue step. Thanks again!
Edit 2: You can now fletch darts on the surface of Entrana for the clue step.