dont want to go there, but with tens of thousands of users using it fine, would indicate its not a general problem either…
and if I were you, and thought caching were off, I would very much want to know why every page on my server is outputting this message in the page source:
<!–Cached using Nginx-Helper on 2013-07-02 15:01:58. It took 75 queries executed in 5.844 seconds.–>
<!–Visit http://wordpress.org/extend/plugins/nginx-helper/faq/ for more details–>
did you try the change in the link provided?
and you can search our code, no way for us to change any path to fake path…
so at this point, at little more detective work needed… lets rule out the wp theme or another plugin (though I would suspect something on server like image protection especially if caching is running without your knowledge)…
Try a temp switch to the default wp theme… and see if still occurring.. then disable all other plugins and see if it still occurs…