Command failure is ignored when embedded inside PDQ

For the deployment of software developed for internal company usage I simply pack all files into a zip, copy that over to the deployment repository, and during deployment run a script that copies the content of the zip marked as latest version to the intended computers.

Now I wanted that step to fail with the errorlevel of the command that was run and failed in the script. When I insert the batch and simply call it, this works as intended: script fails => step fails => error code get's shown in the status of the step, parts of the deployment are marked as failed.

If I insert the content of the batch file as command into the appropriate step the step finished successfully - even though the script itself fails and half of the work isn't even done. The whole deployment is thus marked as successful.

Any idea on what i'm doing wrong?

Here's the batch code I use for deployment:

:: installation
if exist "%SOFTWARE_PATH%\%APP_ID%-%APP_VERSION%.zip" (
 Setlocal EnableDelayedExpansion

 :: finish running app...
 %SYSTEMROOT%\system32\taskkill.exe /f /im %APP_BINARY%
 :: ...wait for app to finish
 timeout 1
 :: remove existing version
 if exist "%INSTALL_PATH%" (rd /s /q "%INSTALL_PATH%" || exit /b !errorlevel!)

 mkdir "%INSTALL_PATH%" || exit /b !errorlevel!
 :: copy new version
 "%DEPLOY_PATH%\7za" x -y "%SOFTWARE_PATH%\%APP_ID%-%APP_VERSION%.zip" -o"%INSTALL_PATH%" || exit /b !errorlevel!
 :: copy license files
 if exist "%LICENSE_PATH%\%APP_ID%.zip" ("%DEPLOY_PATH%\7za" x -y "%LICENSE_PATH%\%APP_ID%.zip" -o"%INSTALL_PATH%" || exit /b !errorlevel!)

 :: register application
 if exist "%INSTALL_PATH%\setup.reg" (reg import "%INSTALL_PATH%\setup.reg" || exit /b !errorlevel!)
 :: create desktop link to binary
 if exist "%INSTALL_PATH%\%APP_BINARY%" (powershell "$s=(New-Object -COM WScript.Shell).CreateShortcut('%PUBLIC%\Desktop\%APP_NAME%.lnk');$s.TargetPath='%INSTALL_PATH%\%APP_BINARY%';$s.Save()" || exit /b !errorlevel!)
 Endlocal
)

On another note: originally I've unpacked the zip's content (line 27) using the scripting host inside a powershell command:

powershell "$shell=New-Object -com Shell.Application;$dest=$shell.Namespace('%INSTALL_PATH%');foreach($item in $shell.Namespace('%SOFTWARE_PATH%\%APP_ID%-%APP_VERSION%.zip').Items()){$dest.CopyHere($item, 0x14)}" || exit /b !errorlevel!

This works fine as long as i start this using administrative and elevated rights from the console. But whenever i call this script from pdq deploy the execution stops right there without any output at all.

Any ideas on that as well?