Forcing prompt=login on a session extend overrode DisablePromptLogin, which
is set for IdPs that break on it: Authentik triggers a double authentication
and social logins fail outright. Overriding it there trades a recoverable
extend for a login that cannot complete at all.
Keep the LoginFlag override, which only replaces max_age=0 or none with
prompt=login so the IdP honours login_hint, and leave DisablePromptLogin as
configured. Those deployments keep the silent flow, and with several accounts
signed in an extend answered from the wrong one still fails the user match.
A session extend must be answered from the account the peer is registered
under. With a silent PKCE flow (DisablePromptLogin or max_age=0) the IdP
answers from whatever session it already holds, which need not be the
peer's account when several are signed in; the token then fails the
user match in ExtendAuthSession with no way to pick another account.
Mark the PKCE flow request as a session extend so the management server
can force prompt=login for it, overriding the configured silent flow.
Zoltán Papp