Second book for boss atlas tree points refuses to drop.

Can someone tell me if this is a known bug or not or if something changed in how this is supposed to progress now from how it went in .1? I haven't seen anything on it I could find.

Currently, I've got multiple T15 and T16 waystones that have been completed, fully 6-modded, on maps with bosses, irradiated, and either cleansed or corrupted. I think the last count was somewhere in the 15-20 range between both 15s and 16s that have been done. I even did a T16 fully kitted on a boss/irradiated/corrupted nexus. I got the first book a few weeks ago and haven't had another drop since, no matter how jacked I try to get the maps. If I remember correctly from .1, doing the correct map at each level with a boss (79, 80, 81, 82) would drop a book, and then the last two points come from the arbiter.