The processmail script is hard-coded to look for sendmail at /usr/lib/sendmail. On my Postfix installation, sendmail is only located at /usr/sbin/sendmail. The Bugzilla-generated emails would fail on such an installation.
Assigning to the Powertools maintainer. Tim
Closing as WONTFIX due to end of life of the Power Tools product line. Please open a new bug report under the Red Hat Linux product if the component is still included in the base Red Hat distribution.