New Post: Execute-Process hanging after setup.exe completes

I've got a new installer for a backup agent, and my install script is using Execute-Process:

Execute-Process -Path "$dirFiles\WinX64\Setup.exe" -Parameters "/silent /play Install.xml"

I looked at the processes with ProcExp. I see Deploy-Application.exe, it's child powershell.exe spawn setup.exe. setup.exe spawns msiexec, and then a qinstaller.exe process, and a few others throughout the install. After the software gets installed the setup.exe ends, but the powershell.exe doesn't. However, when I kill one of the backup agent processes (laptop2taskbaricon.exe), then powershell.exe quits, and the rest of the deployment script finishes. So I'm guessing that it thinks the laptop2taskbaricon.exe process is a part of the original setup, and therefore waiting for it to end before continuing after the Execute-Process command?

I can add the -nowait parameter, but then the SCCM app detection starts before the application finishes installing, and fails.

any ideas on this?