Is this a bug - service does not start on boot

[William Colls]

Debian 8.4 (jessie) 64 bit
Nullmailer 2.0 locally compiled

When the machine boots everything seems to start correctly, except this one:

nullmailer.service - Nullmailer relay-only MTA
    Loaded: loaded (/lib/systemd/system/nullmailer.service; enabled)
    Active: failed (Result: start-limit) since Sat 2016-05-07 14:57:22 
EDT; 1min 38s ago
   Process: 787 ExecStart=/usr/sbin/nullmailer-send (code=exited, 
status=203/EXEC)
  Main PID: 787 (code=exited, status=203/EXEC)

May 07 14:57:22 freeswitch systemd[1]: Unit nullmailer.service entered 
failed state.
May 07 14:57:22 freeswitch systemd[1]: nullmailer.service start request 
repeated too quickly, refusing to start.
May 07 14:57:22 freeswitch systemd[1]: Failed to start Nullmailer 
relay-only MTA.
May 07 14:57:22 freeswitch systemd[1]: Unit nullmailer.service entered 
failed state

It turned out that nullmailer.service file ExecStart pointing to the 
wrong location. When pointed to the correct path, service starts fine. 
However the error message is less than helpful.

Should I be reporting this as a bug?

Thanks for your time.

William.