Cannot convert the "System.Object[]" value of type "System.Object[]" to type "System.Management.Automation.SwitchParameter".

I am having an issue when running a swtich option in my script.

I am trying to take group the batchID results and then combine the unique names and join them

If ($CSV) {
    $MBX = Get-CSVFile
    $MigUsers = $MBX.emailaddress | Get-MigrationuserStatistics | 
    select identity,batchid,status,statusdetail,@{label='ErrorSummary';Expression={$_.errorsummary.split('>')[0]}},percentagecomplete,bytestransferred

    $batch = $migusers.batchid.name | group-object | Select-Object -Unique -ExpandProperty name
    $batchname = $batch -join ", "
    }

But I keep receiving the error :

Cannot convert the "System.Object[]" value of type "System.Object[]" to type
"System.Management.Automation.SwitchParameter".
At D:\MigReport-V2.1.ps1:54 char:5
+     $batch = $migusers.batchid.name | group-object | Select-Object -U ...
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [], RuntimeException
    + FullyQualifiedErrorId : ConvertToFinalInvalidCastException