Wordpress does not refresh pages, but loads the cache? Unclear?

Question

WordPress

In general, I have been suffering for about 2 hours and I do not understand what the problem is. site on vp. The bottom line: I connected to the hosting via FTP, edit for example sidebar.php, upload the edited one back, reload the page and 0 effect. Through the hosting admin panel, the effect is the same. The data in the file is updated somehow randomly every 5/10/15 minutes. Which way to look? first time I'm facing this. This doesn't happen with css.

Answer 1

If this only happens to php files (not js, css or pure html - which can be easily checked), then it's most likely one of two things:
1. PHP Opcache. The hoster has configured a rather long lifetime of the bytecode cache, respectively, during this period a cached compiled version will be issued. It will be updated only after the expiration of the cache lifetime.
2. Full-page caching is enabled, that is, you are given a pre-generated html version of the page, the request does not reach PHP at all. Again, will only update when the cache expires.
More details can be obtained from the host.

Answer 2

sidebar - what is it? php file?
alternatively you have applied a theme that has this sidebar overridden