my interpretation is that kris is so empty and hollow following the events of chapter 4’s weird route, that there is simply nothing crossing their mind when interacting with stuff. they’re feeling nothing, and so you don’t get any flavor text. it’s representative of how kris is feeling.

in a more meta way, i think it’s also meant to reference creepypastas (where "there’s nothing where you’d expect stuff to be" is a common trope), and going out of bounds in general, where there’s often not flavor text because you’re not meant to interact with the stuff there. the chapter 5 weird route in general is about going oob, so maybe that’s a foreshadowing.

at least, that’s how i interpret it!