invited attendees - someone receives a meeting notice that was not

[Guest]

When inviting attendees to a meeting, four specific people were sent the
Outlook meeting notice and one person whom wasn't invited received the
meeting invitation too. How did this happen?

 

[Guest]

One of the four original attendees forwarded it to the fifth person without
notifying the meeting organizer first. One of my personal meeting ettiquette
pet peeves, but one that does happen often....

 

[Guest]

Thank you for your reply.
I still have a question. It couldn't be anything else? Maybe a delegate
setting? Maybe a distribution list?
I ask because our county prosecutor sent the original invite to four
prosecuting attorneys and one staff memeber. The individual who received the
message and should not have was the former prosecuting attorney (now a common
pleas judge).