Jason Fyre
Dockworker
I'm still having this issue as well. It began, just as it did for a number of others, when I logged off without turning in the final stage of my quest first. Ever since then I haven't even been able to re-complete it since it quite consistently glitches out and disappears from my journal whenever I'm at the stage that involves brewing the 3 Ghastly Visages among other things. Relogging also has a strong tendency to make the quest disappear.