No message ID in registration emails

[engr_dood]

My forum has manual registration of new members by admin only, using the Admin, Members, Registration, Register New Member menu.  I received a bounce message from a prospective member saying this:

[email protected]
(generated from [email protected])
SMTP error from remote mailer after end of data:
host xxxx.xyz [zzz.zzz.zzz.zzz]: 550-RFC2822 says that all mail SHOULD have a Message-ID header.
550 Most messages without it are spam, so your mail has been rejected.

Is this an issue with my host or with SMF?

Edit:  I did a couple of experiments.

First was to use my host's email server to send an email to myself using Thunderbird.  Result:  Message ID present.

Second was to use the "News" feature of SMF to send an email to myself using my host's email server.  Result:  No message ID.  So it looks like an SMF thing.  Should I report this as a bug?

Edit 2:  I'm using SMF 2.0 RC5