I found the issue... any thoughts on what this means to you and how I can fix it? The bounce handler cleared out the emails so it did its job.
2018/01/25 23:50:01 [error] [system.db.CDbCommand] CDbCommand::execute() failed: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '159-22596' for key 'cid_sid'. The SQL statement executed was: INSERT INTO `mw_campaign_bounce_log` (`bounce_type`, `processed`, `campaign_id`, `subscriber_id`, `message`, `date_added`) VALUES
yp0, :yp1, :yp2, :yp3, :yp4, NOW()).
2018/01/25 23:50:01 [error] [application] CDbCommand failed to execute the SQL statement: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '159-22596' for key 'cid_sid'
2018/01/26 00:50:02 [error] [system.db.CDbCommand] CDbCommand::execute() failed: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '159-1231' for key 'cid_sid'. The SQL statement executed was: INSERT INTO `mw_campaign_bounce_log` (`bounce_type`, `processed`, `campaign_id`, `subscriber_id`, `message`, `date_added`) VALUES
yp0, :yp1, :yp2, :yp3, :yp4, NOW()).
2018/01/26 00:50:02 [error] [application] CDbCommand failed to execute the SQL statement: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '159-1231' for key 'cid_sid'
2018/01/26 01:20:02 [error] [system.db.CDbCommand] CDbCommand::execute() failed: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '159-68740' for key 'cid_sid'. The SQL statement executed was: INSERT INTO `mw_campaign_bounce_log` (`bounce_type`, `processed`, `campaign_id`, `subscriber_id`, `message`, `date_added`) VALUES
yp0, :yp1, :yp2, :yp3, :yp4, NOW()).
2018/01/26 01:20:02 [error] [application] CDbCommand failed to execute the SQL statement: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '159-68740' for key 'cid_sid'
2018/01/26 01:30:02 [error] [system.db.CDbCommand] CDbCommand::execute() failed: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '148-17191' for key 'cid_sid'. The SQL statement executed was: INSERT INTO `mw_campaign_bounce_log` (`bounce_type`, `processed`, `campaign_id`, `subscriber_id`, `message`, `date_added`) VALUES
yp0, :yp1, :yp2, :yp3, :yp4, NOW()).