Combined CSS is loaded but not executed

Silverstripe Version: 4.4


in the page.php i have put the code for the merge. the merged CSS file is also created in “public/assets/_combinedfiles” on the server (comb-style-62cde17.css).
Also the path to the CSS file is output properly in the . However, the CSS file is not loaded. In the dev tools under “network” a 200 code is displayed. If I select an HTML element in the code via “Elements”, then the CSS file and the corresponding classes are not displayed in “Styles”.
In pupic/.htaccess the rewrite base is up: RewriteBase ‘/public’.
Question: Why is the loaded CSS not executed?

        protected function init()