Why does modifying the “read more” link remove the link class?

by

Perhaps there is an issue with the “Ellipsis” HTML character you are using?

function modify_read_more_link() {
    return '<a class="more-link" href="' . get_permalink() . '">( Continue &hellip; )</a>';
}
add_filter( 'the_content_more_link', 'modify_read_more_link' );