Why sometimes redirect_canonical?

When I create a new wordpress site, and I clone it from the production server to the development server (copy the filesystem, copy the database, edit wp-config.php to use the copied database), I can browse to http://prod.server.com and I can browse to http://dev.server.com, and they both work. I do not get a redirect to the canonical URL.

I work at a university with hundreds of wordpress sites. Generally speaking, all of our production sites, if I copy them to a dev server, and browse to the dev server, then I get redirected to the canonical URL. We also have load balancers that perform status checks on servers, so they’re browsing to IP addresses directly via http://a.b.c.d. The load balancers seem to get redirected.

I’m trying to understand (disable) how to control redirection to the canonical URL. I’m aware of “wp search-replace”, but that doesn’t help the load balancers, which are browsing to IP addresses instead of URL’s.

Redirection to canonical URL is something we do at the load balancer, so ideally, I would like to 100% disable wordpress redirection to canonical url’s. Is there an environment variable I can set, or something like that?

Why do some sites redirect and others not? There is no .htaccess (we’re running nginx). There is no Redirect module installed.

Thanks…