So basically I can't do the Judgement bird Abno battle. I'm at the Reverb Ensemble and want to fully realize every floor before I start it. But for some reason even though I have all the books it asks for (being Red Mist Nikolai and Myo) it won't let me enter the book and says I haven't gotten the book of Nikolai and Myo. Is there just some other mission I'm missing or is this a bug?