Почему браузер вместо 403 возвращается 404?

Question

[Kolya Vantukh]

Возникла странная проблема . На вызов http_response_code(403); возвращается ответ с кодом 404 . Если вызывать http_response_code(); с любим другим кодом, тогда все ок . В чем может быть дело?
.htaccess

# 1.To use URL Alias you need to be running apache with mod_rewrite enabled.

# 2. In your opencart directory rename htaccess.txt to .htaccess.

# For any support issues please visit: http://www.opencart.com

Options +FollowSymlinks

# Prevent Directoy listing
Options -Indexes

# Prevent Direct Access to files
<FilesMatch "(?i)((\.tpl|\.ini|\.log|(?<!robots)\.txt))">
 Require all denied
## For apache 2.2 and older, replace "Require all denied" with these two lines :
# Order deny,allow
# Deny from all
</FilesMatch>

# SEO URL Settings
RewriteEngine On
# If your opencart installation does not run on the main web folder make sure you folder it does run in ie. / becomes /shop/

RewriteBase /
RewriteRule ^sitemap.xml$ index.php?route=extension/feed/google_sitemap [L]
RewriteRule ^googlebase.xml$ index.php?route=extension/feed/google_base [L]
RewriteRule ^system/download/(.*) index.php?route=error/not_found [L]
 
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !.*\.(ico|gif|jpg|jpeg|png|js|css)
RewriteRule ^([^?]*) index.php?_route_=$1 [L,QSA]