结果表明，这是由函数中的以下自定义主题过滤器引起的。php。注释已修复该问题。

function image_alt_tags($content) {
    global $post;
    preg_match_all(\'/<img (.*?)\\/>/\', $content, $images);
    if (!is_null($images)) {
        foreach($images[1] as $index => $value) {
            if (!preg_match(\'/alt=/\', $value)) {
                $new_img = str_replace(\'<img\', \'<img alt="\' . get_the_title() . \'"\', $images[0][$index]);
                $content = str_replace($images[0][$index], $new_img, $content);
            }
        }
    }
    return $content;
}
add_filter(\'the_content\', \'image_alt_tags\', 99999);

add_filter(\'post_thumbnail_html\', \'thumbnail_filter\', 99, 5);

function thumbnail_filter($html, $post_id, $post_thumbnail_id, $size, $attr) {
   // you can alter the resulted HTML here
   $html = preg_replace(array(\'/alt=\\".*?\\"/\', \'/title=\\".*?\\"/\'), \'\', $html);
   return $html;
}