Bug in Microsoft Lync 2013 client?

Many users report the issue: http://social.technet.microsoft.com/Forums/lync/en-US/c5bf2775-d195-4f3a-944d-733d707ab698/multiple-ls-storage-service-32054-errors?forum=lyncdeploy

This is the error that appears in EventLog when using Lync 2013 mobile.

Log Name:      Lync Server

Source:        LS Storage Service

Date:          12/4/2013 10:18:02 AM

Event ID:      32054

Task Category: (4006)

Level:         Error

Keywords:      Classic

User:          N/A

Computer:      xxx

Description:

Storage Service had an EWS Autodiscovery failure.

UnsupportedStoreException: code=ErrorIncorrectExchangeServerVersion, reason=GetUserSettings failed, smtpAddress=xxx@xxxxx, Autodiscover Uri=https://autodiscover.xxxx/autodiscover/autodiscover.svc, Autodiscover WebProxy= ---> Microsoft.Exchange.WebServices.Data.ServiceRequestException: The request failed. The remote server returned an error: (401) Unauthorized. ---> System.Net.WebException: The remote server returned an error: (401) Unauthorized.

   at System.Net.HttpWebRequest.GetResponse()

   at Microsoft.Exchange.WebServices.Data.EwsHttpWebRequest.Microsoft.Exchange.WebServices.Data.IEwsHttpWebRequest.GetResponse()

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverRequest.InternalExecute()

   --- End of inner exception stack trace ---

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverRequest.InternalExecute()

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetUserSettings(List`1 smtpAddresses, List`1 settings, Nullable`1 requestedVersion, Uri& autodiscoverUrl)

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetSettings[TGetSettingsResponseCollection,TSettingName](List`1 identities, List`1 settings, Nullable`1 requestedVersion, GetSettingsMethod`2 getSettingsMethod, Func`1 getDomainMethod)

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetUserSettings(List`1 smtpAddresses, List`1 settings)

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.InternalGetSoapUserSettings(String smtpAddress, List`1 requestedSettings)

   at Microsoft.Exchange.WebServices.Autodiscover.AutodiscoverService.GetUserSettings(String userSmtpAddress, UserSettingName[] userSettingNames)

   at Microsoft.Rtc.Internal.Storage.Exchange.ExchangeContext.SendGetUserSettingsRequest(StoreContext ctx, String smtpAddress)

   --- End of inner exception stack trace ---

   at Microsoft.Rtc.Internal.Storage.Exchange.ExchangeContext.SendGetUserSettingsRequest(StoreContext ctx, String smtpAddress)

   at Microsoft.Rtc.Internal.Storage.Exchange.ExchangeContext.GetUserEwsSettings(StoreContext ctx, String smtpAddress, CacheMode cacheMode)

Cause: Autodiscovery Uri was not correctly configured or unreachable, that there is a problem with the Proxy, or other errors.

Resolution:

Check event details.  Check autodiscovery Uri is properly configured and reachable. Check that proxy setting is properly configured and reachable.  Validate Lync to Exchange Autodiscovery configuration by following the trouble shooting guide. If problem persists, notify your organization's support team with the event details.

UPDATE: http://support.microsoft.com/kb/2912341

 UPDATE2: KB is not available from MS.