Because the mission is bugged to hell.
The Outriders demo has been out for several hours already, and if you are like me you might have hit a roadblock. Partway through the mission “Reunion” you end up coming across a set of rocks with the mission statement “clear the rocks.” The problem? Those rocks aren’t clearing for some. Furthermore, the quest isn’t even processing to that point for others.
A few minutes prior you fight a Vanguard Captain with the power of the phoenix. He wields an ability that when active (indicated by a green circle) allows him to come back from the dead. All you have to do is wait for the green indicator to go away and then kill him before he casts it again. During this fight instead of dying he might disappear. This is your first indicator that the mission is bugged.
TL;DR: Leave The Area
Unfortunately the best way I found to fix both of these is to leave the area and come back. If the Vanguard Captain pops out of existence instead of dying, leave the area and you’ll receive a warning and a countdown to come back. Let the countdown expire and the game will turn you around and force you back into the area. Go back to the arena and the Vanguard Captain will be by himself ready to kill again.
After killing the Vanguard Captain the mission should change to “clear the rocks.” At this point if you approach the rocks and the game doesn’t let you interact with them you’ll need to backtrack yet again. This time you need to go all the way back to the safe area, load in the hub, and then go back out to the combat zone. The enemies in the area won’t respawn, so you’ll just have to go back to where you were.
At this point the rocks should have cleared themselves. All that is left is to kill the boss. My character not leveling up (shown below) was another sign the mission bugged.
Hopefully this helps someone.
MMO Fallout 