Opera in turbo mode 404 header page blank page why?

Question

PHP

In the script, I set header("HTTP/1.0 404 Not Found"); if the page is not found. Well, today I noticed that it is not the text of the page that is displayed, but an empty one. I killed the whole day - I was looking for jambs in the script, in the settings. And after 9 hours it dawned on me. When the turbo mode is enabled in Opera, for some reason, when setting such a header, their proxying server returns just an empty page. Who faced? How can this problem be solved? Is there something wrong with htaccess? I have everything there
AddDefaultCharset UTF-8
Options -Indexes
php_value session.cookie_httponly True
RewriteEngine on
ErrorDocument 404 /404.html
Options +FollowSymLinks
RewriteCond %{HTTP_HOST} ^www.dip24\.com$ [NC]
RewriteRule ^(.*) $ dip24.com/ $1[R=301,L]
RewriteCond %{REQUEST_FILENAME} !^favicon\.ico
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
And a bunch of RewrtiteCond and RewriteRule rules, but they don't matter.

Answer 1

The cant was with sending headers to the browser, nothing to do with the opera. Understood.