Unofficial Skyrim Legendary Edition Patch

The order of the stages of a quest isn't important, because they do not automatically progress through them in any way. In this case, what that trigger will do is restart the quest, after it's been stopped when the stage is set to 20.

It might do that on your second time through, if you've waited long enough for it to reset, but the first time through, the quest won't be running because the only thing that triggers it to start is the trigger at the end of the first level. All the other stages are conditional on the quest being active already and at a specific stage. I've confirmed this both in the CK and in the game. The dialogue isn't spoken at all by anybody on your first pass through unless you sneak to the end of the dungeon without killing anyone, then come back, which is pretty counter-intuitive.

It's debatable whether the quest needs to be reset at the end of the dungeon, but it certainly needs to be triggered at the start or you'll never hear any dialogue.

Fixed for USLEEP 3.0.1.

The initial quest stage trigger should have been set up to run stage 0 rather than trying to stop it entirely. It appears as though the level designer did not take into consideration that the cell could be entered from either door.

Yeah, at least to my mind, the way it was setup was the unintuitive way. It requires that you climb the mountain to get to Volsung, then enter the dungeon from there. (In which case, I think the whole puzzle becomes moot.) I think most people would enter from the larger, easier to get to entrance where the marker is.

Anyway, thanks for the fix, Arthmoor!