The only page /manual displays "404 Not Found", how to fix it?

Question

PHP

Parameters of .htaccess files:

AddDefaultCharset UTF-8

Options -Indexes
RedirectMatch 301 (^/*.php$|^/pages/*/$|^/assets/*/$) /

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php [L,QSA]

That is - even if the file does not exist, it redirects the request to the main page. Whatever you enter works as it should... but it's "/manual" that outputs 404. Maybe apache2 saved the cache from the old version of the local site?
In general - how to fix it?