Hello John, thanks for your answer.
I have no problems with my own shortcodes or shortcodes in general, but only if the shortcode comes from a plugin and outputs a code template will I get these unwanted line breaks. For example with Ulitmate Member Plugin, WPForo or finally I tried to use the email download link plugin (https://de.wordpress.org/plugins/email-download-link/).
My template is entirely based on ACF. All fields of my template are saved in an array. Instead of the expression “the_field (‘prefixed_field_name’)” I use “echo $ field_output (‘field_name’)”, because I remove the prefix beforehand.
