Hello,
I am unable to reproduce the issue, on all my ENVs, $HOSTNAME/kmc redirects to http://jessex/index.php/kmc/kmc4, as it should.
Considering how from Admin Console->Publishers->Your Partner->Actions->Manage it does work correctly, I wouldn't spend much time debugging it. You can just edit /opt/kaltura/app/start/index.php and instead of:
<a href="/kmc" target="_blank">Kaltura Management Console (KMC)</a>Set:
<a href="/kmc/kmc4" target="_blank">Kaltura Management Console (KMC)</a>However, if you do want to debug it, a good place to start would be /opt/kaltura/log/kaltura_prod.log and /opt/kaltura/log/kaltura_apache_access.log