Hi,

In the browser the text is displayed like this:

rendered by prince it's displayed this way:

The font I use is Oswald (Google Fonts)
(<link href="https://fonts.googleapis.com/css?family=Oswald:300,400|Roboto:100,300&subset=latin-ext" rel="stylesheet">)

I Hope you have an idea

Can you attach or email me (mikeday@yeslogic.com) some sample HTML? Perhaps there is something strange happening with combining accent marks.

This issue turned out to be caused by the Oswald font missing combining accent marks. The solution is to use precomposed characters (eg. u-with-umlaut as a single character). This can also be done automatically using the prince-text-replace CSS property to modify the document text.