Page float specified on ::first-letter pseudo-element causes "TypeError: Cannot read properties of null (reading 'firstPseudo')".

Example:

<style>
p::first-letter {
  float: top;
  float-reference: page;
}
</style>
<p>Lorem ipsum dolor sit amet consectetur, adipisicing elit.</p>

Test with Vivliostyle Viewer (v2.27.0):
https://vivliostyle.github.io/viewer/v2.27.0/#src=https://gist.githubusercontent.com/MurakamiShinyu/073b773d08910334acc4e337d15f95cf/raw/page-float-on-first-letter.html

Screenshot: