Consider the following scenario:
You have a desk telephone that is running Microsoft Lync 2010 Phone Edition.
You log on to the desk telephone, and then open the Settings page.
You select Date and Time Format, and then set a date format.
You open the Call Logs page or the Voice mail page.
In this scenario, the date format is not saved on the Call Logs page or on the Voice mail page. This issue occurs when the desk telephone uses one of the following languages:
To resolve this issue, install the following cumulative update:
2577593 Description of the cumulative update for Lync 2010 Phone Edition for Polycom CX700 and LG-Nortel IP Phone 8540: July 2011
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.