My season character at lvl 58 and long past completing Fughar's Memorandum doesn't have access to Igor's log.
My primary character is lvl 61 and has completed Witch of Horrors but also does not have access to Igor's log.
Hi there, please check with the black spirit, he should have a quest to unlock it.
Found it! Thank you! Annoying that none of the guides on this mention this part.
To be fair to the guides, these "unlock" quests have only been added about 3 weeks ago, many of the guides did not get updated since then.