I had the same problem today. When you check to source code you can find :
add_filter(‘the_content’, [ $this, ‘fixContentUrls’ ], 20);
Which it search in the content and modify the link domain(if it was different) for the currently domain.
You just need to add an action in your child’s theme functions.php like this :
function remove_fixContentUrls()
{
if (!class_exists(‘MultipleDomain’)) {
return;
}
$multipleDomain = MultipleDomain::instance();
remove_filter(‘the_content’, array($multipleDomain, ‘fixContentUrls’), 20);
}
add_action(‘init’, ‘remove_fixContentUrls’);
And it works fine for me. I hope it helps you and other as well