The lag is definitely not generally fixed, I am still encountering it today. Nothing moves in Wyrmrock Fortress. I can enter with my avatar and run around, but all NPCs are stationary and silent, followers not following.
This problem only occured for me when entering Wyrmroch Fortress the 2nd time. The first time was completely fine, getting the waypoint and clearing the dungeon. Then I when back to Rivington because I forgot something, and now it's f***ed up.
I thought it might be a server network issue, since at one point I got some strange "disconnect" message and was thrown out of my game to the main menu.