If I'm reading this whole conversation correctly, the issue is that the game offers you the option to make Shadowheart leave, she agrees to do so but then proceeds to remain in your camp anyway. Her being sworn to guard the artefact has nothing to do with that. It's clearly either a bug, an oversight or an Early Access thing, @JandK and others are completely in the right here.
It's early access some lines need to be made clearer but that's not particularly relevant here. The intent of her character is abundantly crystal clear...she's not going anywhere. If you're somehow confused about that the final game should clarify that you can dismiss from party but not from camp...at least not without her being driven mad and attacking.
