Apple Books: swipe left goes to next chapter instead of next page

When I try to change pages in Apple Books (swipe left or right, or tap on the left or right side), I am now taken to the first page of the next (or previous) chapter! This started sometime early 2025. I thought it was a glitch, but it has been persistent for months. Closing the app and powering off the phone to restart has not helped.

I noticed this is happening only in the free e-books offered by the publisher (Baen) and author (David Weber). I can navigate all other books normally.

This is quite annoying as I like re-reading my favorite books and the e-format is more convenient than lugging around my hardcover copy.