What are you talking about? They have completely different eyes (and mouths.)
While there are some panels that aren't as drastically stylized, they all follow that pattern. Droopy eyes, goofy smile = Chinatsu; wider, angular eyes, tiny mouth = Miharu.
Is there an inconsistency? In the first page, it looks like Natsuko and Haruko kiss to swap back, but don't (as seen in page 2). Or was that the preparation to kiss?
I notice that the images here are named “V2.png” through “V9.png”, as if a V1.png were omitted.
And, previously, what has been called the first chapter of a volume has been eight pages, the first ten of which were not actually from the first chapter but from the beginning of the volume.
Other volume chapter 1s have more pages because they are from the volume version. These are the monthly magazine scans. I'll add the extra pages when the volume comes out in a couple of months.