ZO is denying this being a bug:
Greetings Brave Warrior of The Covenant Not,
Thank you in advance for contacting The Elder Scrolls Online Support Team!
We do apologize for the inconvenience this in game issue might be causing you.
Regarding your issue, I may see brave hero, that your will to protect the land, help others and free us of the will of Molag Bal is grand. Unfortunately, in these days evil is spread all around and from commoners to nobles and even royals all need aid. You may find them in the most far away or hidden places. They may ask you to aid them with small tasks or with big deeds. I invite you to once again explore the land in all these places, big and small, high and low, dungeons, caverns and fields in search of such people. Many times I have found those in need of help that I hadn't before when revisiting the beautiful lands that are under the rule of the Covenant.
Due to game mechanics I may not provide more information but I do invite you to search on the forums and ask other players as they may provide valuable information on quests that you may be missing.
Hello,
From my understanding, your having problems with the achievement. This is a known issue that we are currently investigating. I apologize for the inconvenience, I assure you I haven't lost you, and this ticket is getting escalated to a team that handles in game bugs. Once again, I apologize for this issue and the misunderstanding.