…and you experience WTF case when your content somehow seems not to be refreshed despite calling
Reasons and solutions are described in the ZendOptimizerPlus issue #126.
It can be solved by using
$realpath_root in the nginx config:
fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name; fastcgi_param DOCUMENT_ROOT $realpath_root;
It worked for me and huge thanks go to Vitaly Chirkov.