With the described configuration, I have a SQL Agent Job that includes a Powershell step. That step throws an error when it gets to the line
$app = start-process -passthru $program $program_args
"The error information returned by PowerShell is: 'The term 'start-process' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again. '. Process Exit Code -1. The step failed."
The lines preceding this seem to work ok. I suspect that the Powershell host that is running the script is crippled regarding that function but I am not able to verify this anywhere.