Solved
The Descent -- Second Rune-Warded Gate BUG
Playing through the DLC a second time, and I've encountered a game-breaking bug at the Darkspawn nest. After pulling the lever to open the gate, I see the scene where shrieks are mobilizing, but then...
Weird solution: the "stuck on black" problem doesn't seem to appear if I go from using 4xMSAA to using 2xMSAA. Increasing the anti-aliasing after the Shriek scene works fine.
