Some Ubercart emails are not being logged

I'm running Ubercart 5.x-1.7. Mail Logger doesn't seem to be logging the "customer checkout notification" or "admin checkout notification" emails ("admin/store/settings/notify/edit/checkout"). Also, when I update the status of an order and check the "send email notification on update" checkbox, Mail Logger doesn't seem to log this either.

The Mail Logger module claims to log "all outgoing mail that passes through drupal_mail function". Perhaps the code responsible for sending out the above emails does not utilize the drupal_mail function, but use a different mail function instead? This would explain why these emails are not being logged. If these emails are being passed through the drupal_mail function, then there may be a bug in the Mail Logger module.

Thanks!