Kind of made me sad. If she hadn't grown when his friend complimented her it would've been cliched but other than the red string of fate type nonsense, they could've done it more interesting in a way, causing them to delve into why it was that she was only growing when he complimented her (and then it would tie into how she'd already gotten attached to him in the prior chapter) Perhaps that she's become a sort of onryo or "vengeful spirit" of sorts, haunting him as the lore would do of her other targets, and having the lewd comic as part of it perhaps.
I just hope we don't get some "insecure Japanese herbivore MC" trope (which is overused CONSTANTLY in manga these days) that gets drawn out for who knows how many chapters. It would suck if that happens.
However... THANK YOU TO TL FELLOW OF CULTURE