<p><br>some text</p>

With the above markup, prince won't render the space the br gives in the editor

If the text begins with two <br> both are rendered.

When I convert this document with Prince it gives similar results to the browser:

<style>
p {
    border: solid red thin;
    background: yellow
}
</style>
<p>some text</p>
<p><br>some text</p>
<p><br><br>some text</p>

Are you applying some other style rules?

Hello @mikeday, I am using some styles but everything works well but the <br> as the first element in a paragraph.
I was thinking it was the font (I am using Google Fonts) but it is not. I isolated the problem to the br tag.

Can you try the document I have shown above and see how it behaves?

Here are the two output files (html and pdf)

1. html.png‎ 28.8 kB ‎
   html output
2. pdf.png‎ 111.7 kB ‎
   pdf output

Would you be able to email me (mikeday@yeslogic.com) the HTML and CSS?