Error when updating Client Access Front End Service to Exchange 2013 Update 6

When updating to Exchange 2013 Update 6 we received the following error at the Step 11 of 13: Client Access role: Client Access Front End service step: 

Error:
The following error was generated when "$error.Clear(); 
          $fe = get-ActiveSyncVirtualDirectory -server $RoleFqdnOrName -DomainController $RoleDomainController -ErrorAction SilentlyContinue;

          if ($fe -eq $null)
          {
            new-ActiveSyncVirtualDirectory -DomainController $RoleDomainController -Role ClientAccess;
          }
          else
          {
            update-ActiveSyncVirtualDirectory $fe -DomainController $RoleDomainController -InstallIsapiFilter $true
          }
        " was run: "System.Management.Automation.ParameterBindingException: Cannot convert 'System.Object[]' to the type 'Microsoft.Exchange.Configuration.Tasks.VirtualDirectoryIdParameter' required by parameter 'Identity'. Specified method is not supported. ---> System.NotSupportedException: Specified method is not supported.
   at System.Management.Automation.ParameterBinderBase.CoerceTypeAsNeeded(CommandParameterInternal argument, String parameterName, Type toType, ParameterCollectionTypeInformation collectionTypeInfo, Object currentValue)
   --- End of inner exception stack trace ---
   at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input, Hashtable errorResults, Boolean enumerate)
   at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext funcContext)
   at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
   at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)".

Problem was that if you have more than one ActiveSyncVirtualDirectory, the installer for Update 6 fails because it's not expecting an array of virtual directories to be returned. Solution is to remove the "extra" virtual directory, perform the installation, and then re-add the virtual directory. 

None of the other types of virtual directories are susceptible to this, only ActiveSync.