We're using the API explicit flow for identity brokering in our Keycloak SSO server to provide users with the option for logging in using their Stack Overflow account.
Recently, we've noticed that Stack Exchange API seemingly started to ignore the port number specified in the
redirect_uri parameter. E.g., when Keycloak is running on 8080 port, user is redirected back to port 80 (or 443 respectively if HTTPS was used) after logging in to Stack Exchange.
In other words, Stack Exchange is ignoring port number and is using the one based on current protocol leading to an error if Keycloak is running on a port which is non-default for given protocol.
After investigating this we were unable to find anything wrong on Keycloak's side. For that reason I'd like to ask if anything changed in the API regarding the ports in redirect URIs, or if it's an issue and an unexpected behavior. If so, is there any way to officially report it?