I can no longer login through package manager on publish instance after installing the latest service pack 6.5.8. I can still through: /libs/granite/core/content/login.html. I'm just wondering if I've missed something in the release notes, maybe?

You can get the URL from the request.  You could map those URLs to a property (OSGI configuration for the Servlet) that you can use to determine what data to send back or for processing down a different path. Translations would have to be done regardless - request would have to have something to let...

Right, I'm pretty sure that is what I wrote in my comment on 10-08-2020

Hotfix-CQ-4312194-FELIX-6252-1.0.zip

Get the Hotfix mentioned in the comments of this thread.

@Kunal_Gaba_