PowerShell Script not functioning correctly when scheduled Task

$sessionOptions = New-Object WINSCP.SessionOptions -Property @{
   Protocol = [WinSCP.Protocol]::Sftp
   HostName = "Hardcoded SFTP site name"
   UserName = "Hardcoded SFTP username"
   SshHostKeyFingerPrint = "Hardcoded FingerPrint"
   SshPrivateKeyPath = "Hardcoded relative path to .ppk file"
   PrivateKeyPassphrase = "Hardcoded Passphrase"
}
 
$sftpSession = New-Object WinSCP.Session    
$sftpSession.SessionLogPath = "C:\Automation\SFTPSessionLog.txt"
 
TRY {
   $sftpSession.Open($sessionOptions)      #-- Open SFTP session 
 
   # Force binary mode transfer
   $transferOptions = New-Object WinSCP.TransferOptions
   $transferOptions.TransferMode = [WinSCP.TransferMode]::Binary

#-----------------------------------------------------------
#       Installing needed roles/features
#-----------------------------------------------------------
Add-Type -Path "WinSCPnet.dll"
Add-Type -Assembly "System.IO.Compression.FileSystem"
 
#-----------------------------------------------------------
#       Variables
#-----------------------------------------------------------
$date = Get-Date            # Current Date
$temp = "C:\Automation\TEMP\"
$destination = "C:\Automation\SFTPTransfer\"
$logFile = "C:\Automation\logs\"        # Log file
sftpSource = "/IntegrationFiles/"
$sftpFileCount = 0
 
#-----------------------------------------------------------
#   FUNCTIONS
#-----------------------------------------------------------
    #Function:  ScriptLogging()
    #Purpose:   Unified logging function that outputs all messaging passed to it to both a log file 
    #           as well as the console.
    #Inputs:    $serverity = Message type (INFO, DEBUG, ERROR)
    #           $message = The message that is to be logged to file / console
    FUNCTION ScriptLogging($serverity, $message) {
        [String]$timeStamp = (Get-Date).toString("yyyy-MM-dd HH:mm:ss")    #-- Get current timestamp
        [String]$logLine = "[{0}] | {1} | {2}" -F $timeStamp, $serverity.PadRight(5), $message
 
        #-- Write to both a Logfile and Pipeline
        IF (($serverity -NE "") -OR ($message -NE "")) {
            $logLine | Tee-Object -FilePath $logFile -Append | Write-Output
        } ELSE {
            ScriptLogging "ERROR" "Failed to pass required parameters to ScriptLogging Function"
            EXIT 1
        }
    }
   
   
    #FUNCTION:  CheckSFTPTransfer()
    #PURPOSE:   Check that all files downloaded from the SFTP sites
    FUNCTION CheckSFTPTransfer($sftpDownloadResults) {
 
        #-- Check SFTP transfer for Errors
        FOREACH($transfer in $sftpDownloadResults.Transfers) {
            IF ($transfer.Error -EQ $Null) {
                ScriptLogging "INFO" "  File transfer successful: $($transfer.FileName)"
            } ELSE {
                ScriptLogging "ERROR" " File Transfer failed: $($transfer.FileName)"
                ScriptLogging "ERROR" " Transfer Error Message: $($transfer.Error.Message)"
                Exit 1
            }
        } 
    }
 
#-----------------------------------------------------------
#   MAIN
#-----------------------------------------------------------
    #-- Create Log File
    $logFile = $logFile + "SFTPTransfer_" + "$($date.Year)" + "$("{0:D2}" -f $date.Month)" + "$("{0:D2}" -f $date.Day)" + ".log"
    New-Item -ItemType File -Path $logFile -Force | Out-Null
    IF (!(Test-Path -Path $logFile)) {
        Write-Output "|ERROR| Logfile failed to created, exiting execution."
        EXIT 1
    }
 
    IF (Test-Connection -ComputerName SFTP -Count 1) {     #-- Test Connection to SFTP server
      ScriptLogging "INFO" " SFTP server responded to ping"
 
      # Build SFTP Session Options Object (Yes these values are hardcoded, see comment above)
      $sessionOptions = New-Object WINSCP.SessionOptions -Property @{
         Protocol = [WinSCP.Protocol]::Sftp
         HostName = "sftp"
         UserName = "SomeUserName"
         SshHostKeyFingerPrint = "ssh-rsa 2048 FingerPrint"
         SshPrivateKeyPath = "C:\Automation\2020.ppk"
         PrivateKeyPassphrase = "APassPhrase"
      }
      ScriptLogging "DEBUG" $sessionOptions
 
      $sftpSession = New-Object WinSCP.Session    #-- Create sftp session variable
      $sftpSession.SessionLogPath = "E:\EncoreOnPlayNow\SFTPSessionLog.txt"
      #$sftpSession.SessionLogPath = "C:\Automation\EncoreOnPlayNow\SFTPSessionLog.txt"
 
      TRY {
         $sftpSession.Open($sessionOptions)      #-- Open SFTP session 
 
         # Force binary mode transfer
         $transferOptions = New-Object WinSCP.TransferOptions
         $transferOptions.TransferMode = [WinSCP.TransferMode]::Binary
 
         #-- Get Count of number of files on SFTP site
         $sftpFiles = $sftpSession.ListDirectory($sftpSource)
         FOREACH ($fileInfo in $sftpFiles.Files) { 
            IF ($fileInfo.Name -Match ".csv") {
               $sftpFileCount++
            }
         }
         ScriptLogging "INFO" " Number of files contained on SFTP site: $($sftpFileCount)"
 
         #-- Download files from SFTP to temporary location
         $sftpTempDownloadResults = $sftpSession.GetFilesToDirectory($sftpSource, $temp)
         ScriptLogging "INFO" " Downloading to $($temp)"
         CheckSFTPTransfer $sftpTempDownloadResults  #-- Check SFTP transfer was successful
 
         #-- Download files from SFTP to SFTPTransfer location
         $sftpTransDownloadResults = $sftpSession.GetFilesToDirectory($sftpSource, $destination)
         ScriptLogging "INFO" " Downloading to $($destination)"
         CheckSFTPTransfer $sftpTransDownloadResults #-- Check SFTP transfer was successful
                        
      } CATCH {
         ScriptLogging "ERROR" " Failed to connect too and download files from SFTP site".
         ScriptLogging "ERROR" " Exception: $($exception)"
         Exit 1
      } FINALLY {
         $sftpSession.Dispose()       #-- Disconnect session
      }
    } ELSE {
        ScriptLogging "ERROR" " SFTP Server did not respond to ping"
        Exit 1 
    }

[2020-07-12 10:52:39] | INFO  |  SFTP server responded to ping
[2020-07-12 10:52:39] | DEBUG | SomeUserName@sftp         
...