Exchange 2013 sp1 cu7

A user sent a message to everyone in the GAL. 

From Outlook 2013, if you hit reply on this message, the recipient that appears in the To: field is not the original sender, but is someone else in the GAL.

From OWA, if you hit reply, the To: field shows the original sender. The original message was not sent from OWA as our users do not have access to it.

In the header of the message in Outlook, the Reply-To & Return-Path fields are different

How did/could this happen?

Thanks!

If Outlook is doing what you say it's doing--and I would check it yourself instead of taking the word of an end user--then it would be a bug in Outlook and I would open an incident with Microsoft Support.

He probably used the "Direct Replies To" option in Outlook. Take a look at this article.

• Proposed as answer by Ed CrowleyMVP 6 hours 32 minutes ago

l logged into the sender's mailbox and yes, the rogue name was in the 'Have replies sent to' field for this message.

What's odd is that there was no reason for him to do this.....the name in the field is a user in another department, completely unrelated to the original sender.

I spot-checked other messages in his Sent Items and did not find any other instances of this, so it does not appear to be an attack..  However, the sender was not necessarily a savvy user, so I would be surprised if he did this manually.....that's why I was concerned. 

I have been here many years and have never heard anyone else complain of this issue, so I guess it was just a one-off.

Also, it's odd that OWA replied to the correct sender, like it ignored the Outlook setting completely.

Thanks to you both for your replies.

You're welcome.  Please feel free to mark Albert's post as the answer.