When redicting, the phg file is downloaded, how so?

Question

Nginx

We decided to remove Apache, set up redirects in nginx, everything seems to be working. But I noticed that when you click on the link (js windows.open works there), in fact, opening a new window, instead of a new window, the browser offers to download the file. What was my surprise when I opened the file and found my code, the file was without an extension. The file is downloaded to which the redirect is going for further work of the script, and there are several such links, the rest open normally.