I was clearing the Lab section and got a message saying the zone will do a full repop in 5 minutes. I do not know if this was some kind of fix that was pushed or if this is a new bug. Approximate time of zone repop was 9:40pm EST on Friday night.
Hotfix Notes: April 20, 2018 *** Quests and Events *** - Removed the chance for one of the clues to spawn on an inaccessible NPC.
I heard from others on server a repop happened. I didn't start the task till after that so it did not affect me.