Because the first eighty chapters of A Dream of Red Mansions are recognized as Cao Xueqin's manuscripts, and the last forty chapters are Gao E's sequels. When I first made this TV series. The first eighty chapters are based on manuscripts, and the last forty chapters are based on Zhi Yanzhai's comment on writing and the literature of Redology researchers. The reason for this is to restore a true dream of red mansions, not to distort the plot as Gao E did.
The plot you are talking about is a sequel to Gao E, of course I can't see it.
Say something superfluous. I hate Gao E's "gifted scholar". I wrote that Wang Xifeng became the designer of the switch plan. I hate to write that Baoyu, who married Baochai, is stupid without psychic jade ... I can see that Xifeng is saving Baochai's love with Grandmother Jia, and Baoyu is not necessarily stupid to lose psychic jade. But everyone is defeated and sees through the world of mortals, and so is Stone (psychic Baoyu). He finished his fantasy and returned to Geng Qingfeng.