The IPA helper for the server installer looks for the existence of either a user-provided keytab or /etc/httpd/conf/ipa.keytab. If it is found then installation continues. It never looks in the keytab to see if the creds exist and/or are valid.
This issue ticket was originally removed from the tracker as it clashed with the pull request. See upstream ticket for migration details.
Metadata Update from @t0xic0der: - Issue close_status updated to: Fixed - Issue status updated to: Closed (was: Open)