在设置规则之前，必须删除筛选器。请参见下面的代码示例：

// Sync user role
add_action( \'set_user_role\', \'sync_user_role\', 10, 2 );
function sync_user_role( $user_id, $role ) {

    $blogs = get_blogs_of_user( $user_id );

    $blogs_count = count( $blogs );

    if ( $blogs_count > 1 ) {
        foreach ( $blogs as $blog ) {

            $user_blog = new WP_User( $user_id, \'\', $blog->userblog_id );
            remove_action( \'set_user_role\', \'sync_user_role\', 10);
            $user_blog->set_role( $role );
            add_action( \'set_user_role\', \'sync_user_role\', 10, 2 );
        }
    }
}