Why is Group Email Automatically High Priority

[Marc Harmon]

Whenever I send group email, I get a copy back that is set to highest
priority. I expect the copy, just not the priority setting. Why does this
happen? I have no evidence of this setting with the outgoing message sitting
in the outbox. Settings here say normal.
[Sending group email = New mail message, type group name in address field,
calls forward all email addresses set in that group.]
Thanks,
Marc