The boss' second blight didn't spawn, softlocking the mission. I tried to backtrack down the big shaft leading to the room before the boss where you take the portal, but that didn't fix it. I stayed dead for a few minutes, which just triggered enemy spawns until it stopped, but the second blight still didn't spawn. If it helps, I was in the solo ops quickplay node, just trying to get rid of 3 bonus engrams there.