Entered the ruin with a new alt in pursuit of Ruuvitar, logged out to continue later.
When I relogged I did not spawn near the ruin entrance or outside the door as per usual in these circumstances but in the inner chamber that quest-wise was still locked. Ruuvitar was there alright so I smashed him to pulp but understandably the quest line didn't quite manage to adapt to this development so I had to return to the ruin proper and do the door opening phase before returning to kill Ruuvitar again and proceeding with the quest.
So, nothing major but might be a bit confusing experience to a newbie.