Blade of woe not working during Signed in Blood quest

fiender66

With my last (for now) magblade I had to complete the quest without the Blade of Woe (then relying on the cloak, BTW). The indication with the buttons simply did not appear, ever.
BoW worked fine before and after the quest.
I've done the quest other times with other NBs, and noticed that BoW performed erratically, but never it disappeared altogether