Chrome has a heuristic they call SSLCommonNameMismatchHandling: if Chrome tries to connect to a site like "https://example.com" but the returned cert is for the "www." subdomain of the same domain, Chrome will silently redirect to "https://www.example.com".
Chrome has a heuristic they call SSLCommonNameMismatchHandling: if Chrome tries to connect to a site like "https://example.com" but the returned cert is for the "www." subdomain of the same domain, Chrome will silently redirect to "https://www.example.com".