Incorrect Rendering of Chinese Fonts in EPUB Books
After reading a few chapters, the font SimSun (宋体) or STKaiti (楷体) will automatically change to PingFang (苹方), which is the default font for Chinese books. The fonts can be correctly rendered after reopening the book, but the same issue will appear again after reading a few chapters.
(Image source: apple图书无法中文设置字体)
Same issue posts:
iPhone 13 Pro Max, iOS 16