Afaik that is the normal umask for a VM's files on VMFS.
I wouldn't change those.
Can you run the following little script.
I want to make sure that all the files in the folder actually belong to the VM, and are not some left-over files
$vm = Get-VM -Name vmName
$vm.ExtensionData.LayoutEx.File |
Select Name
And could you also try changing the Connect-VIServer line in the script of the scheduled task.
Do it as
$vcServ = Connect-VIServer -Server vc.domain.com -user servername\Administrator -password password
Yes, I know that is hardcoding the credentials and not secure, but just as a test to check if there is something wrong with the stored credentials.