The story has highlighted Kurumi as being a fairly oblivious person at points. Like how chapter 3 had Kurumi openly admitting to Isanuma that she's basically clueless about love. Or how in chapter 7 Kurumi told Kokoro that she's never been in love with anyone. Volume 3's bonus chapter also had Kurumi thinking that Naoi has an odd sense of personal space. Basically, because Naoi's offbeat nature, Kurumi's often at a loss on how to interpret her actions. It seems like Kurumi didn't really see the date as intended to be romantic on Naoi's end. Which is an important thing to note. In fact, Kurumi and Kokoro were still a couple in chapter 18 because Kokoro rejected Kurumi's attempt at breaking up with her in chapter 16. It would also explain why Kurumi seems so confused everytime Kokoro brings up Naoi, which would only make sense if Kurumi hasn't consciously realized her feelings for Naoi are romantic yet.
Naoi's feelings are also hard to parse. She basically admitted to liking Kurumi to Kokoro in chapter 6, but the volume 3 bonuses had a segment that implied that Naoi's mentally linking Kurumi to her little sister. It's possible the story could go in that direction for now, and have the chapter 6 line as intented as only Naoi teasing Kokoro. Because at this point Kurumi and Naoi confessing seems unlikely until they sort some of their issues out and Kurumi actually dumps Kokoro and has it stick.
