missing subjects on alert emails

Has anyone seen the problem where 'MAIL' recipients receive messages
with no subject?  Am I missing a configuration option here?  Note that
alerts are sent fine, but the subject is empty.   Here is the config
line from hobbit-alerts.cfg.  Note that I blanked out the company
domain.

HOST=%sac-p* SERVICE=* EXSERVICE=conn
        MAIL user-1d4faaf71e14@xymon.invalid COLOR=red,yellow