The chapter of the novel presents some interesting points. Please be aware that the excerpts were translated using MTL.
Here, we see that Yuu lied to his parents about his activities, which strengthens the hypothesis that he was keeping his relationship with Yami a secret from them—though the reason remains a mystery. Additionally, it's interesting that Yuu still regretted failing his entrance exams and that Yami didn’t consider the implications of his statement.
Here, we see that Yami lies constantly, and Yuu is aware of it. This is an obvious red flag.
Here, we see that Yami is clearly obsessed with Yuu, which raises another red flag.
Apologies for the lengthy post, but it's a shame that the manga is a shortened, butchered version of the novel. To me, it really seems like publishing both the novel and the manga simultaneously was a mistake.
Thanks for the chapter!