I don't think we can necessarily discount the grip/alignment at address factor in some cases.
I think it's been fairly established that a lot of amateur/recreational players, when they set up to the ball, are aligned (shoulders and feet) right of the fairway target. So if they have the club square to the fairway target - it's automatically gonna look like the face is closed at address, providing their shoulders and feet are aligned right of the target and the face is square to the fairway target.
Again, this is in some cases, not all.
I do struggle with this myself from time to time, albeit from the other side since I'm a lefty.