Once again, Kyotaro's overt self-consciousness caused him to be a good boyfriend here. He felt iffy, so he went ahead and was honest to his consistently jealous girlfriend. As cringe and in denial as he is, our boy is always sincere and that's why he's cool.
I wonder how protective Kana is of her little brother? She takes quite good care of him, so I can see this getting ugly with Momo before it gets better.
I know I'm going against the grain on this, but I kind of trust this author so much that I'm confident that the misunderstanding will get solved in a page or two. It's a feeling I'm still getting used to
It's so nice being able to trust an author to handle a trope you're tired of well because they have a good track record.
I predict a quick resolution or even moving past it to some other issue they have with this scene beyond misunderstandings.