> Compounding this problem was a bug in the MTA that caused the MTA to crash that occurred only when it received a message with more than 8,000 recipients. But it crashed only AFTER processing up to 8,000 recipients. So 8,000 of the 13,000 recipients of the message would get it and 5,000 wouldn’t.
When the MTA was restarted, it would immediately start processing the messages in its queue – and since the messages hadn’t been delivered yet, it would retry to deliver the message, sending to the SAME 8,000 recipients and crashing.