I'm looking on it, it's just say :You can't go back if you've never been there yet.
The quest is from the last version, read the changelog.
Go to Krowly’s lab and read the book you have found during the quest with Golem Nun and Brother Volt. If you have finished that quest but haven’t found the book, you can still return to the dungeon and find it.
The book I have, Krowly can't read it actually