I've seen reports of this bug from as early as 2021. And it still not fixed. As far as I can tell it may be connected to going through the illusory fire in the hut and then going back. After that attacking Ethel there transforms her, but after that she just stands there not attacking (but taking a long time doing nothing during her turn). You can kill her there and she'll just take it. Going down the stairs moves her inside and the dialogue goes as normal until you get down to the cage where she shows up but still does nothing (also nothing happens to the cage). Getting her down to the hp threshold starts the dialogue about the deal and you can bargain with her. After that she disappears, but I have no idea if her ai is still going to be broken later when you meet her again.
