I'm using version 4.1.3 with the snippet:
Show-ADTInstallationWelcome -CloseProcesses "PanGPA", "PanGPS" -ForceCloseProcessesCountdown 3600
Show-ADTInstallationProgress -StatusMessage "Global Protect is installing, please wait before connecting to VPN."
I've deployed this to ~30 devices via Intune. All but 7 completed with out issue. On the 7 with problems, I find this in the logs:
It never gets to the actual installation and appears that Show-ADTInstallationWelcome itself is exiting with code 1618. The logs show that the Intune retries the install 3 more times, with five minutes between, but each time it exits the same way. My first thought was the Show-InstallationWelcome command is checking if other MSI processes are busy, but it doesn't seem like that could be it after checking the MsiInstaller log on the affected computers: Get-WinEvent -ProviderName MsiInstaller. I remember a feature in past versions that allowed the install to wait for the MSI server to be available but I don't see that parameter any longer.
