Problem with acquiring Map Boss Skill Points 6/10

Hello,
i have problem with Map Boss Skill point tree, i am stuck at 6/10, i have done all combinations on Tier 15 maps till 81 monster level and done Tier 16 map on Monster level 82. No book dropped, all i did was i finished the monster level 79 book and then i have done a jump at some point skipping one monster level (cant remember which one) to Monster level 82 and dropped book. Now i am stuck at 6/10, i miss one book (2 points) cause another 2 are from finishing Pinnacle fight with Arbiter boss. Can't progress further and the fact that it doesn't show which difficulty i didn't finish to receive the points ain't helping too.