Killed Executioner, Freed Leitis, but cannot advance to Manor

I cannot climb the stairs to go to the portal to the Manor even though I have killed the Executioner and freed Leitis. The objective says infiltrate the Manor. The objective indicator on the map is at the location of the lever that freed Leitis.

I found that I was able to fast travel to the Manor Ramparts waypoint in spite of having never been there yet.