There is a bug in the documents application (I am using the latest version for Windows x64). In a document, if you already have some text written on a page and then decide to insert a page break, the following happens:
Normally, when you select a heading, write some text, and press “Enter,” the text style returns to “Normal.” This stops happening.
If you type “-” and press the spacebar, the list view with “–” is automatically generated. This also stops happening; the item appears on the screen as you type, but it remains empty and shows strange tabulations while nothing is written.
I have not discovered any more inconsistencies related to this so far, but I consider this information sufficient to point out that the “page break” function has some bugs.
I add this video to show how to make it: https://youtu.be/Hq6gH4ZRAE8