Article ID: 2498410 - View products that this article applies to.
Consider the following scenario:
To resolve this issue, install the following cumulative update:
(http://support.microsoft.com/kb/2496325/ )Description of the cumulative update package for Lync 2010: April 2011
After you apply this update, you can configure the EnableContactMergeUsingProxyAddress setting to disable merging contacts that are based on secondary SMTP addresses.
To work around this issue, you can manually remove the email address of the user from the Outlook contacts.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.