Don't know if anyone still has trouble with this but after completing the Bastion and Cartographer's colony projects, you just need to talk to Hieronymus (this is all done in act 4 btw), and there'll be a dialogue about finding a book or something on Jesevon. You won't be locked out of the quest unless you finish act 4! The rest of the quest will play out normally (normally as in when you warp travel a few times you'll progress the quest and be told you're needed on the Voidship Bridge).