Not sure with the event over it would be considered spoiler to post, but did you read the wowhead guide?
It was working when I did it, so if it does not work now, you should put in a bug report, but make sure you follow the guide to.
You have to enter Karazhan through the front gate, and work your way up to the library thatβs just past The Curator. The tomes are in the old version, not the new version.
Entering on the bridge no longer takes you to the upper half. It will take you to the revamped dungeon that was released in Legion.
This is a great pointβ¦Iβve seen a few people get tripped up on this quest chain by doing that. Legion content is pretty easily soloable now, so if someone isnβt intimiately familiar with both versions they might not even realize theyβre in the wrong one.