Powershell Encoded Command not executing

Question

I have a powershell script that runs as part of an installshield installer on a machine with Windows 10. Powershell version (Major: 5, Minor: 1, Build 17134, Revision 112). Dev machine (where everything works fine) (Major: 5, Minor: 1, Build 15063, Revision 1155)

Basically, a .bat script runs an encoded powershell command, but it is not executing, I simplified it down to a simple script to show what I am talking about:

Powershell Script:

$text="Write-Output Hello"
$encoded=[Convert]::ToBase64String([System.Text.Encoding]::Unicode.GetBytes($text))

Write-Output "Trying encoded command:"
powershell -EncodedCommand $encoded

Write-Output "Trying not encoded command:"
powershell $text

This is the output:

Trying encoded command:
Trying not encoded command:
Hello

I also added a decoded statement to do an additional check:

$decoded = [System.Text.Encoding]::Unicode.GetString([Convert]::FromBase64String($encoded))
Write-Output "Decoded:"
Write-Output $decoded

Output:

Trying encoded command:
Trying not encoded command:
Hello
Decoded:
Write-Output Hello

The execution policy is set to "Bypass", i'm just wondering if there is something in the windows registry/settings/security/group policies/etc. that will block encoded commands like this? Why does it work in plain text but not encoded? Could the Powershell version have anything to do with it?

Answer 1

Turns out there was a block from the AV on encoded commands. Thank you @TessellatingHeckler