@TiaraFSeiei besides the point provided by kutiltanic, they actually address this question during the trial. It seemed like the actual reason is a secret only known by the empress, duke Nuremberg and possibly, the red-haired uncle. Maybe it does have something to do with the late empress.
I know there are some debate about the MLs, either it's Jeremy or Nora. IMHO, taking the character's point of view, even if Jeremy loves Shuli (in that way) in the new timeline, he will not pursue his feelings. One of the reason is that he has fully accepted his position as her 'son' and even swore his loyalty to her as the current head of the family. He acknowledges Shuli's position as the guardian so I think he wouldn't see himself as her potential partner unless he has truly grown as a man worthy of Shuli. And by that time, he will (probably) see that the choice is up to Shuli and he might not be chosen. So for now, he will only act as her oldest son.
As for Nora, I think his feelings for her amount to only a crush currently. He calls her 'noona', although quite intimate, it implies that she is above him. So he still needs a lot of growing up to do, being more mature and gaining his own influence like in the old timeline. I am definitely rooting for Nora.
After this arc, I assume there will be a time skip 🤔
But the title of 'epilogue' for this arc really worries me 😥