The latest questline Coup De Grace for Crow in Destiny 2 is bugged. The High Celebrant is proving to be quite tricky to chase down in the Ascendant Plane. Currently doing too much damage to the High Celebrant in the Coup De Grace weekly mission will bug this mission and prevent you from activating the Ascendant Plane, forcing a restart of the mission.
Here is exactly how we worked around the High Celebrant bug in the Coup De Grace mission. First off, and most importantly do not do too much damage burst damage in the first phase of this mission.
Step 1. Place the lure inside the mission to spawn the High Celebrant.
Step 2. Let him spawn start doing small amounts of damage, he is going to port to the center of the room. Use primary ammo until the Knights spawn.
Step 3. Kill the Knights then stand in the green glow and continue to tick down his health. Do not use high damage like Anarchy or Xenophage as you might do too much burst damage and bug him out.
Step 4. Continue slowly ticking down damage until you reach about 50% health within the first chunk of his health bar. The High Celebrant will have three chunks of damage, you are looking to get the first third down to about 50% health.
Step 5. Once that first chunk of health has about 40-50% damage dealt refrain from high damage and stick with Primary Ammo. Continue to pepper him down until he teleports under the arch.
Step 6. Stop damaging him once he is under the Arch.
Step 7. Crow will begin speaking once he disappears, leave him and the Blight Orb alone. Do not shoot anything.
Step 8. Let Crow speak his full voice line, once he is done, wait 10 seconds and then shoot the Blight Orb. So long as you didn’t burst him down too quickly this will spawn the Ascendant Plane.
REDDIT recommends doing this solo, we have also had success with this solo, however, we have determined based on our own trial and error that the bug is activated by doing too much burst damage to the High Celebrant.
Second Section Bug: Engage the High Celebrant
After going through the Ascendant plane you will encounter the High Celebrant a second time. You will be engaging him on a circular platform. Take the remaining first third of health, leaving him with his remaining 2/3rds health. Allow him to stand for a brief moment before the mission is complete.
The step should now saw Destroy The Residual Energy. Shoot the Blight orb after you see this mission segment change.
Third Potential Bug
On the final step of “Execute the High Celebrant,” you will want to get his health down to about 15% of his last third chunk of health. A Barrier Servitor will spawn, take this barrier out first before killing the boss to prevent any more bugs from occurring.