Hi Insiders,
We have a new update for you, build 16.0.6568.2036.
To get the update, click File > Account > Update Options > Update Now.
This update fixes two significant POP3 issues in Outlook 2016:
- After Outlook downloads email, all email messages on the server are deleted from the Inbox.
- Email messages are downloaded multiple times from Outlook, causing duplicate items.
In addition, we've fixed an issue where Office apps would crash if you attempted to convert a file to PDF using Adobe Acrobat PDFMaker.
Special thanks to Insider Mrs. Richardson for being the first to bring the POP3 issues to our attention!
Source: Announcing Insider build 16.0.6568.2036 for Office 2016 on Windows - Microsoft Community