Similar thing with surebackup job and custom script for testing that dhcpservice is running.
Without custom script the job perfoms corerctly.
The job log contained this errors:
[SureBackup] [VMName] [ScriptTests] Begin 'Custom script 1: name Query DHCP service, starting...'
Failed to create process with net logon (-1073741816) (System.Exception)
As temporary solution Microsoft KB3139914 has been uninstalled according to Veeam KB https://www.veeam.com/kb2132