Yes. If you kill a witch in the shape of an animal, then the grimoire will not fall. IMHO is still a bug, not a feature.
P.S. Also these grimoires look like usual and if you do not know about the quest you can accidentally sell them and then forget where you sold
Hello!
I took the Nemok`s quest for 3 grimoires, but the witch Bipara was killed before taking the quest. And now I do not know where to get a grimoire.I again searched her empty dwelling and found nothing. I found the save before she was killed and again killed her. The grimoire was not there. To get her grimoire I needed from the beginning to take the quest? Somehow this is not correct. Please tell me what to do now. Rollback save too far