Blank "Reported By" and "Assigned To" in email

[maclark99]

Version 1.1.6 of Mantis.

I get emails from mantis but the reported-by and assigned-to fields are always blank:

The following issue has been UPDATED.
======================================================================
http://www.example.com/view.php?id=539
======================================================================
Reported By:
Assigned To:
======================================================================

Is this some kind of configuration option?