Missing full path to Sitemap in virtual robots.txt

[kohlermedia]

The function witch generates the virtual robots.txt strips the path ​https://mydomain.com/sitemap.xml to /sitemap.xml.

Tested with

<?php
add_filter( 'robots_txt', 'robots_mod', 10, 2 );
function robots_mod( $output, $public ) {
        $output .= "Sitemap: https://mydomain.com/sitemap.xml/\n";
        return $output;
}

in functions.php

sitemaps.org notes
"You can specify the location of the Sitemap using a robots.txt file. To do this, simply add the following line including the full URL to the sitemap: Sitemap: ​http://www.example.com/sitemap.xml"

Google search console marks a sitemap without full path as error.

[kohlermedia]

Printscreen of google search console robots.txt tester

[ocean90]

Hello @kohlermedia, welcome to WordPress Trac!

Thanks for your report. I couldn't reproduce the issue on a clean install. In core we have no function that would replace the domain there.

Try disabling all plugins and maybe activate a default theme to find the cause for this. For additional help, please try our ​Support Forums.