I started this achieve for the Harrison follower 13 days ago. I've completed 5/6 and I'm only missing "Breaching the Barrier." This starts with the Harrison quest "Treasure Contract: Explosive Discoveries." The quest has never been offered once in 13 days. I've checked every day and he keeps offering "Gutrek's Cleaver" or some other one, sometimes the same one as the day before.
I don't understand why the dailies aren't just offered in a set order. Is this some form of gating? I don't understand Blizzard's logic here.