Powershell Export-CSV Error - "The process cannot access the file \\xxx\hhh\fff\report.csv because it is being used by another process

Question

Help please - I have a script to report all DFS folder targets and will check the path status but I'm getting a random export-csv error "The process cannot access the file \xxx\hhh\fff\report.csv because it is being used by another process.". It doesn't happen to each of the loop, script will run w/o an error for few loops then I will get the message. I tried adding Start-Sleep from 1-10 secods but still getting the same error.

Script below:

  cls
$Report = "\\server1\DFSReport"
$Date = (Get-Date -format "MMddyyyy")
$Tab = [char]9

$Roots = Get-DfsnRoot -Path 'ABC.com\data'

ForEach ($Root in $Roots) {
        Write-Host
        Write-Host $Tab Enumarating $Root.Path -ForegroundColor Cyan
    $Dirs = Get-DfsnFolder -Path "$($Root.Path)\*" | Where-Object { ($_.Path -notlike '*.DFSFolderLink*') -and ($_.Path -notlike '*test*') }
        Write-Host $Tab Found $DIRs.Count Folder Targets -ForegroundColor DarkCyan

        ForEach ($DIR in $DIRs) {

            $Targets = Get-DfsnFolderTarget -Path $DIR.Path | Select-Object State, Path, NamespacePath, TargetPath, ReferralPriorityClass, ReferralPriorityRank 
            
            ForEach ($Target in $Targets) {
                
                $TF = @{
                        $True  = 'Accessible'
                        $False = 'NOT Accessible'
                       }
                $DFSN = Test-Path $Target.NamespacePath
                    Write-Host
                    Write-Host $Tab $Tab Checking DFSN Path - $Target.NamespacePath - $TF[($DFSN)] -ForegroundColor Cyan
                $NativePath = Test-Path $Target.TargetPath
                    Write-Host $Tab $Tab Checking DFSN Target Path - $Target.TargetPath - $TF[($NativePath)] -ForegroundColor DarkYellow

                $Prop = [ordered]@{
                                 'DFS State' = $Target.State
                                 'NamespacePath' = $Target.NamespacePath
                                 'NamespacePath Status' = $TF[($DFSN)]
                                 'TargetPath' = $Target.TargetPath
                                 'TargetPath Status' = $TF($NativePath)]
                                 'ReferralPriorityClass' = $Target.ReferralPriorityClass
                                 'ReferralPriorityRank' = $Target.ReferralPriorityRank
                                 }

                $Obj = New-Object -TypeName PSObject -Property $Prop
                Write-Output $Obj | Export-Csv -Path "$Report\DSFN-Report-$Date.csv" -NoTypeInformation -Append
                Start-Sleep -Seconds 4
            }
        }
}             

Added Start-Sleep, maybe someone can help what am I doing wrong here.