All artifact dialogues seem just "glued" on top of the existing plot in a weird way with shadowheart being like " No no, it makes complete sense, let me explain". Which goes completely against what was suposed to be her " secretive nature" .
I’d certainly agree that the handling of the artefact could be better and some of the explanation doesn’t (yet?) make perfect sense, but Shadowheart hasn’t struck me as being massively forthcoming about it. At least until she’s grown to trust the PC or until the box does its thing outside the goblin camp after which it makes sense to me that she’d feel she needed to give some sort of explanation and also might want a second opinion about it once it has a clearer connection to our plight. And even then it feels like there are more questions than answers.