Redirect Site Base Url Doesn't Respect @web alias in craft.

[developingchris]

Describe the bug

Our craft instance is running behind a reverse proxy on an internal domain to our hosting provider. Servd.
But our web application reverse proxies at a different url.(e.g project.production.servd.dev, is proxied to ourproject.com)
Setting the alias and environment variable has been fine for most functions of craft.
However retour redirection is using the internal hostname and not the resulting url in the @web alias.

To reproduce

Steps to reproduce the behaviour:

1. Have a site running on a subdomain, with the web alias running on another subdomain
2. When you curl the page the 302 you are returned will return the unaliased base url.

Expected behaviour

The base url would ultimately read and respect the @web alias placed in the config for the given site as the ultimately base url.

Screenshots

If applicable, add screenshots to help explain your problem.

Versions

• Plugin version: 5.0.6
• Craft version: 5.5.10

[khalwat]

Retour should be reading this setting from the URL set in Settings -> Sites in your Craft setup. Can you verify for me what those are set to in this case with a screenshot or such?