Robocopy - Verzeichnis Timestamps wurden nicht mitkopiert

function Set-FolderDateOldest
{
    Param([parameter(ValueFromPipeline=$true)]$Folder)
    
    Process
    {
        $oldest = Get-ChildItem $Folder.FullName | 
            Sort-Object -Property LastWriteTime |
            Select-Object -First 1
        
        if ($oldest) {
            $Folder | Set-ItemProperty -Name CreationTime -Value $oldest.LastWriteTime
            $Folder | Set-ItemProperty -Name LastWriteTime -Value $oldest.LastWriteTime
        } else {
            Write-Warning "Empty Folder"  
        }
    }
}

$pathDepth = {
    $separator = [System.IO.Path]::DirectorySeparatorChar
    @($_.FullName.Split($separator)).Count - 1
}

$Path = "D:\Documents\TestDir"  
Get-ChildItem -Recurse $Path |
    Where-Object { $_.PsIsContainer } |
    Sort-Object $pathDepth -Descending |
    Set-FolderDateOldest