How to cope with such anomalous behavior of nginx?

Question

Nginx

I came across such a thing: I reinstalled nginx by cleaning out all files, including configuration files, installed debian from the testing distro, I don’t know if it matters, dumped the minimum config into sites available, linked it to sites enabled, then started expanding it to work with php and noticed that the config does not change, I write new rules there, but they do not work. I first completely deleted everything from the config, and then the config itself and the link physically. The site still continued to work, and nginx restarted without errors.
I don't remember what I was doing when this happened.
Maybe this is a dream? Or has nginx learned to cache configs?
nginx version: 1.14.2, before that it was 1.14.1
UPDATE:very strange, I waited half an hour, drank tea, did not touch the PC at all, updated the page with the site, it is now unavailable, now this can be explained by the fact that the configuration file has been deleted. But why was it what it was?
Even before that, I noticed that after restarting, Enginix updates the data in the config after about two page refreshes. But now something is completely blunted. However, the question remains open.
UPDATE 2: everything is set up, everything works. But it does not give rest why there was a problem.

Answer 1

nginx -Vand nginx -Tin the studio. Most likely, you are just "writing in the wrong place" (c), that is, after reinstallation, the path to the main config has changed.