Perhaps after Richard's recent death she re-evaluated some things and wants to move to France to be with Henrik.
If Marge wants to be with her husband after Richard died, I'd be ok with it.
This dinner was announced days before Richard died, so it's not related. A Danish disher could give us a scoop about the current political situation. I remember reading one writting at the time of his election that it would be hard for him to stay in office for the whole term
Marge stated very recently in an interview that she wouldn't abdicate, so if that's the case something happened for her to change her mind