Atlas Skill Point Quest Bugged?

I just finished my second corrupted nexus without progressing the atlas skill point quest with Doryani. Both times I used a t15 map with at least 4 mods where my requirement was only t6+. Both times I killed boss and then waited for the second boss to spawn but it never ended up spawning even after 5+ mins and so I can't progress the quest? All of the maps around the nexuses that I cleared show the 'cleansed' status and the map said 'complete' after the boss even though the corrupted boss never spawned. Am I doing something wrong? Is this a bug?