If several of the deliveries fail, the mailer can send a single bounce message showing all the addresses that failed and explaining what went wrong in each case. It is completely unacceptable for a mailer to lose a message after it has accepted responsibility for delivering it. Sometimes the first attempt to deliver a message is stymied by a temporary problem such as a network outage or a full disk. Note that, if delivery is made, the mailer is not responsible for notifying the sender. This is true even if delivery is delayed.
Some mailers corrupt the envelope sender address, and send subsequent bounces to the wrong address.
This is a violation of the fundamental responsibility of the mailer. Note that, for typical mailing-list messages, the From address is a contributor while the correct envelope sender address is a list manager. Contributors are generally quite annoyed at receiving bounces that should have been sent to the list manager.