Thank you for posting in Microsoft Q&A forum.
You may try below to bypass the execution policy:
cmd.exe /c powershell.exe -executionpolicy bypass -file "%SCRIPTROOT%\Windows_Cust.ps1"
Also, I see you also have a step to run powershell script, have you tried that and what is the result?
If above doesn't help, you may check smsts.log for more details.
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