2 and 3 are HTTP 302 and 301 respectively, both with Location headers. Leaving good practices aside, that's fine, at least I can follow those.
But what if your 301 moved permanently status codes isn’t working as intended or is bringing up the wrong resource? This type of website maintenance is essential in making sure your website is healthy, we will explain the common types of redirect issues and errors and how to fix them.
Первоначальный запрос на http://www.esdc.gc.ca/en/cpp/post_retirement/eligibility.page возвращает страницу, содержащую следующее... <script> window.location.replace("/cgi-bin/op-so/err/404-fra.asp?servertype=apache&p=404;http://www.esdc.gc.ca/en/cpp/post_retirement/eligibility.page"...
...http://www.servicecanada.gc.ca/cgi-bin/op-so/err/redirect-outbound.asp?status=301%20Moved%20Permanently&redirect
A close look at what a 301 Moved Permanently response code is, including troubleshooting tips to
Настройка 301 редиректа в конфигурационном файле NGINX для SEO, 301 Moved Permanently.
The 301 redirects are considered best for upgrading users from HTTP to HTTPS.
This module makes it possible to change URI using regular expressions (PCRE), and to redirect and select configuration depending on variables. The syntax is as follows to chage URI in accordance with the regular expression and the replacement string.
Status: 301 Moved Permanently Code: 301 Content-Type: text/html; charset=iso-8859-1
You either need to connect directly to the redirect URL or have the server return a 308.