If the player when conversing with the Sovereign chooses the 2nd dialogue option "I have slain the creature called Glut. It was scheming to slaughter your circle", despite this option addressing both Duergar and Glut matters at once the Sovereign will not actually award the player with the Bliss Spores buff.
Another issue is that even after the Sovereign ascends the player's title in the Myconid circle from Peace-Bringer to Kin-Spirit for taking care of both threats, he still keeps referring to the player as just Peace-Bringer.