No Boss Atlas points from killing area lvl 82 Boss

Same bug here.

8/10 points on Boss tree (already killed Arbiter)
t16 map
+1 monster lvl on corrupted map
irradiated
Map lvl 82 when looking inside the map

Killed the boss and no book. Maybe you need to have only 6 points on the tree?

Just tested again and worked. The problem is that you NEED to have only 6/10 spent in the atlas boss tree before entering the map. I already had 8/10 spent because I had defeated arbiter before.

Just to resume:

6/10 points spent in the atlas boss tree
monster lvl +1 on a corrupted/cleansed map
irradiated
waystone lvl 16

doing like this and you can have the points.