When you run repeated SEARCH BODY requests in the mailbox by using Standard IMAP4 Commands in a Microsoft Exchange Server 2013 or Exchange Server 2016 environment, newly delivered messages that are reported to the mailbox may not be returned in the search results.
This issue occurs because new email messages aren't detected by existing search queries.
To work around this issue, change IMAP4 search query (such as the casing) to detect new email messages.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
Article ID: 4024652 - Last Review: Jun 27, 2017 - Revision: 7