EDIT: Tried later on a *new* character; Guess that did it? Had to step away from the quest at 4/5 feathers collected, while in the Crow's Nest. IRL stuff, yknow? Anyway, upon returning to resume the quest, the waypoint to resume it is past the barrier in the EDZ; I can't get to the reservoir zone. Abandoning the quest and picking it back up didn't work, and nor did trying on another character.