Since we have the previous vision showing smol Yang and dying adult Dew, possibly something that REALLY want to break these two apart and yet they keep finding the other again.
It's a reincarnation story, Jiang is taking decisions that is modifying it too much, while the other/new Jiang is something like the system trying to fix the story and put it back on track, and since she was the lead designer of the game, the system has her appearance.