OIDC login no longer works after update to 1.20.0

[cmmarslender]

Describe the bug
After updating to 1.20.0, oidc login no longer works

Additional context

Typing in the okta role makes a request to auth_url which is coming back as 403 forbidden. Previously, it would change the state of the login button, which I could then click and log in via okta.

The oidc provider config has remained unchanged since prior to the update, and looks like this:

[cmmarslender]

I was able to work around this for now by logging in with the CLI tool from my laptop:
vault login -method=oidc -path=okta_oidc role=okta_admin

Then putting the token that was provided from that into the token method of login in the UI. So the OIDC provider doesn't seem to generally be broken with Vault, but it doesn't work when using it from the browser in the normal seamless/integrated way of logging in w/ OIDC

[pierresebastien]

It is possible to login through the UI but now you have to specify manually the mount path. On the login page, choose the option 'Sign in with other methods', then select OIDC as Method, fill in the Role (if required) then click on 'Advanced settings' and specify your Mount path (okta_oidc in your case).

Duplicate #31116

[cmmarslender]

I agree with the reporter of the other ticket - this is definitely a regression. This is a change from how the oidc login has worked for many releases (many years of releases). Additionally, once you login with the custom path once (which did work), once that token expires, it takes you to this page, which has no option to enter the custom path again:

So then you have to "sign in with other methods" to back out of this singular screen that Vault is forcing you to, in order to enter a bunch of extra information which did not used to be required.

If you're going to require entering the custom path to log in the first time, fine. But if you remember that was the login method used prior, and are NOT going to remember the custom path used, why continue redirecting the user to the now useless okta oidc login page on subsequent attempts to login?