Given a document like so:
#import "@preview/hydra:0.3.0": hydra
#let hdyra = hydra.with(paper: "a7")
#set page(
paper: "a7",
flipped: true,
width: 100pt,
header: hydra(skip-starting: false, 2),
)
= Chapter
#lorem(5)
#pagebreak()
// = Chapter
== Section
#lorem(5)
The following two pages are rendered:

If the second // = Chapter is no longer commented out, the header on page 2 disappears. This will remain an issue until typst allows us to check the structure of the document more thoroughly to really ensure the first content of a page is the primary element, any of its ancestors or spacing/layout content.
Given a document like so:
The following two pages are rendered:

If the second
// = Chapteris no longer commented out, the header on page 2 disappears. This will remain an issue until typst allows us to check the structure of the document more thoroughly to really ensure the first content of a page is the primary element, any of its ancestors or spacing/layout content.