Breadcrumb items don’t reflect TLD of reverse proxied page

Hello,

Thank you for contacting Rank Math and bringing your concern to our attention.

Could you please confirm if you wanted to change the URL of the first crumb in Rank Math breadcrumbs?

Home >> Crumb1(proxied TLD URL) >> Crumb2(website URL)

You can also share the actual URL and the URL you wanted to use so we can check.

Meanwhile, this could be achieved by using and customizing this filter:

/**
 * Allow changing or removing the Breadcrumb items
 *
 * @param array       $crumbs The crumbs array.
 * @param Breadcrumbs $this   Current breadcrumb object.
 */

add_filter( 'rank_math/frontend/breadcrumb/items', function( $crumbs, $class ) {
    if(get_post_type() == 'post') {    //Change this to match the post type name
        $crumbs[1][1] = 'www.my-site.com';   //Change this to your actual proxied TLD or URL
    }
    return $crumbs;
}, 10, 2);

And here’s how you can add the filter to your site:
https://rankmath.com/kb/wordpress-hooks-actions-filters/

Let us know how this goes.

Thank you.