Went back to it today to get the logs and for whatever reason it started working,
Session.SessionLogPath. Submit the log with your post as an attachment. Note that passwords and passphrases not stored in the log. You may want to remove other data you consider sensitive though, such as host names, IP addresses, account names or file names (unless they are relevant to the problem). If you do not want to post the log publicly, you can mark the attachment as private.
$transferOptions = New-Object WinSCP.TransferOptions
$transferOptions.TransferMode = [WinSCP.TransferMode]::Binary
$transferOptions.FileMask = ".txt"
# Sync files local and delete any that are not on the SFTP
$synchronizationResult = $session.SynchronizeDirectories([WinSCP.SynchronizationMode]::Remote, $SourcePath, $FtpPath, $True, $False, [WinSCP.SynchronizationCriteria]::Time, $transferOptions)
# Throw on any error
# Disconnect, clean up