When you download email from the server using Outlook connector, the date of the Email will become 1970/1/1 and no body, title etc everything.
Deleting the Email will also remove the email from the web UI which indicate the Connector can associate the one in your inbox and the one in Web UI (store).

You can still view Email in Web UI correctly, moving folders, mails around function correctly.

Cause of problem:
In admin console, the user's setting => Attachment Settings => "Disable attachment viewing from web mail UI"
Please select "Attachments can be viewed in HTML and their original format"

That means Outlook Connector share SOAP URL with the WebUI which in turns make the connector retrieve incorrect mail information.

Steps to reproduce the issues:
1. install Zimbra Outlook Connector in two computers
2. in Admin console, make user A select "Disable Web UT", make user B "Attachments can be ...format"
3. send one mail to both users, in outlook download the mail
4. Get inode of both email from the users store, indicate that they share the same file
5. user A will get 1970 mail

Work around solution:
set COS of all users to "Attachments can be viewed in HTML and their original format"

I would like to name this bug as "Year 1970 bug"