I think Yurgir being a trigger is worse, IMO, and IDK why it was changed.
Just briefly then: Of course I can only guess, but using Yurgir as a trigger synchronises it with the Araj encounter. When meeting Araj, you defend his autonomy; when fulfilling Raph's deal, you also support his autonomy because he learns what Cazador's plan for him is and can plot against it. As Marielle wrote above, fulfilling a devil's contract and slaying a mighty beast just so that Astarion can learn something about himself - a very classical romantic gesture if you will XD - seems like a good trigger for a guilty conscience too, while high approval alone maybe doesn't have the same effect.
My theory back then was that Madame Fel was long-lived because of... whatever she was, and had been alive to see Astarion's ruling that got him killed, hence that part of his past would've been addressed because she knew of it and disliked it. It was nice to imagine how things could've turned out in EA.
This would explain why Ulma is so focused on Astarion's redemption in some of her dialogue and seems to think that it might be something he desires.
