Error sending email ... Illegal address

When trying to send even a test email through simplenews (using html/mimemail) I'm getting this error:
Error sending email from validsender@mydomain.com to Array ( [0] => ) : Illegal address

(email address are all valid, but changed to protect the innocent)

Note that simplenews sends without a problem when using normal SMTP or using something like SendGrid.

Here is the entire $message variable (with emails and message body altered for privacy):

Array
(
  [id] => simplenews_test
  [to] => validrecipient@mydomain.com
  [from] => "sender name" 
  [language] => stdClass Object
    (
      [language] => en
      [name] => English
      [native] => English
      [direction] => 0
      [enabled] => 1
      [plurals] => 0
      [formula] => 
      [domain] => 
      [prefix] => 
      [weight] => 0
      [javascript] => 
    )

  [params] => Array
    (
      [context] => Array
        (
          [account] => stdClass Object
            (
              [snid] => 561
              [activated] => 1
              [mail] => validrecipient@mydomain.com
              [uid] => 20053
              [language] => stdClass Object
                (
                  [language] => en
                  [name] => English
                  [native] => English
                  [direction] => 0
                  [enabled] => 1
                  [plurals] => 0
                  [formula] => 
                  [domain] => 
                  [prefix] => 
                  [weight] => 0
                  [javascript] => 
                )

              [timestamp] => 1299261803
              [name] => testuser
              [tids] => Array
                (
                  [102] => 102
                  [103] => 103
                )

              [newsletter_subscription] => Array
                (
                  [102] => stdClass Object
                    (
                      [tid] => 102
                      [status] => 1
                      [timestamp] => 1299261803
                      [source] => ubercart
                    )

                  [103] => stdClass Object
                    (
                      [tid] => 103
                      [status] => 1
                      [timestamp] => 1301321431
                      [source] => mass subscribe
                    )

                )

            )

          [newsletter] => stdClass Object
            (
              [tid] => 103
              [vid] => 5
              [name] => test list
              [description] => a list for testing purposes
              [weight] => 10
            )

          [node] => stdClass Object
            (
              [nid] => 1547
              [type] => daily_alert
              [language] => 
              [uid] => 1
              [status] => 1
              [created] => 1302280568
              [changed] => 1302280568
              [comment] => 0
              [promote] => 0
              [moderate] => 0
              [sticky] => 0
              [tnid] => 0
              [translate] => 0
              [vid] => 1575
              [revision_uid] => 1
              [title] => amazon ses test 2
              [body] => 

This is a test of the Amazon SES send rate.  Had this been an actual email, this description would have been more awesome!

              [teaser] => 

This is a test of the Amazon SES send rate.  Had this been an actual email, this description would have been more awesome!

              [log] => 
              [revision_timestamp] => 1302280568
              [format] => 2
              [name] => admin
              [picture] => 
              [data] => a:4:{s:13:"form_build_id";s:37:"form-7558d4a36b86c97b9a2f9ddd3637f2a1";s:23:"delete_affiliate_points";i:0;s:14:"picture_delete";s:0:"";s:14:"picture_upload";s:0:"";}
              [path] => content/1547
              [simplenews] => Array
                (
                  [nid] => 1547
                  [vid] => 1575
                  [tid] => 103
                  [s_status] => 0
                  [s_format] => html
                  [priority] => 0
                  [receipt] => 0
                  [sent_subscriber_count] => 0
                )

              [last_comment_timestamp] => 1302280568
              [last_comment_name] => 
              [comment_count] => 0
              [taxonomy] => Array
                (
                  [103] => stdClass Object
                    (
                      [tid] => 103
                      [vid] => 5
                      [name] => test list
                      [description] => a list for testing purposes
                      [weight] => 10
                    )

                )

              [files] => Array
                (
                )

            )

        )

      [from] => Array
        (
          [address] => validsender@mydomain.com 
          [formatted] => "mycompany" 
        )

    )

  [subject] => [test list] amazon ses test 2
  [body] => Array
    (
      [body] => Having difficulty viewing this email?  
Click here to view this email on our website.

Amazon SES has amazing throughput... Hopefully we can see these peak values

This is a test of the Amazon SES send rate.  Had this been an actual email, this description would have been more awesome!
Unsubscribe

You are receiving this email because you signed up for our email list at mydomain.com.

If you cannot read this, you need glasses.

Copyright ©2009-2011

 
      [footer] => 
    )

  [headers] => Array
    (
      [MIME-Version] => 1.0
      [Content-Type] => text/plain; charset=UTF-8; format=flowed; delsp=yes
      [Content-Transfer-Encoding] => 8Bit
      [X-Mailer] => Drupal
      [Errors-To] => validsender@mydomain.com 
      [Return-Path] => validsender@mydomain.com 
      [Sender] => validsender@mydomain.com 
      [From] => "mycompany" 
      [Precedence] => bulk
      [List-Unsubscribe] => 
    )

)

I believe this may relate to a known issue:
https://forums.aws.amazon.com/thread.jspa?threadID=59211

I am looking into this further, but would like to use this issue as a means of sharing my experience and to see if anyone else has wrangled with this issue.