Picked up the weekly sparks quest (Ringing Deeps), logged out, and when I relogged into the game, it was just not in my quest log any more. Later on, I was working on it, got about 60/100 sparks, had to log out, and when I returned to the game, once again it was no longer in my quest log. When I picked it up again from the quest giver, I’d lost all progress.
Picked it up a third time, and completed it without logging out, but I wanted to report this bug.
(Lots of screwier stuff has been happening too. I swear a trinket was just outright removed and deleted from my shaman in a delve the other day. I know it was gone because it was an on-use trinket and the button for it was on my bars, but one moment it was there, and the next, I had no item in the slot. Super strange.)