If the target folder does not have a retention policy applied, the retention policy of the Inbox is applied to the items unexpectedly when a Microsoft Outlook rule tries to move the items automatically from the Inbox folder to the target folder.
To resolve this issue, install the following update rollup:
2936871 Update Rollup 6 for Exchange Server 2010 Service Pack 3
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about retention tags and retention policies, go to the following Microsoft website: