After successfully hailing the city guard and getting the update, My character, Mackdaknife, followed the trail to regu praesitor who responds to my dialogue but the task does not update and the trail disappeared. I cannot finish the task, I tried doing the next step, the harried page, but although he responds to dialogue, there is no update. Zoning, reloading character and reloading game did not correct this error.
some ideas in this link https://forums.daybreakgames.com/eq/index.php?threads/disappearing-dragons-bug.284886/
I dropped the task and got it again. Same thing happened at the regu, lost the trail and there was no "X" on the map;however, moving a few steps around the NPC gave me the update. The update point is not exactly where the NPC is. Same situation at the harried page. I guess that's why it tells you to follow the trail and not just hail the NPC.
