How powershell handles returns from & calls - powershell

Question

We have field devices that we decided to use a powershell script to help us handle 'updates' in the future. It runs every 5 minutes to execute rsync to see if it should download any new files. The script, if it sees any file types of .ps1, .exe, .bat ,etc. will then attempt to execute those files using the & operator. At the conclusion of execution, the script will write the file executed an excludes file (so that rsync will not download again) and remove the file. My problem is that the return from the executed code (called by &) behaves differently, depending on how the main script is called.
This is the main 'guts' of the script:
Get-ChildItem -Path $ScriptDir\Installs\* -Include #("*.ps1","*.exe","*.cmd","*.VBS","*.MSI") | ForEach {
Write-Verbose "Executing: $_"
& $_
$CommandName = Split-Path -Leaf $_
Write-Verbose "Adding $CommandName to rsync excludes"
Write-Output "$CommandName" | Out-File -FilePath $ScriptDir\excludes -Append -Encoding ASCII
Write-Verbose "Deleting '$_'"
Remove-Item $_
}
When invoking powershell (powershell.exe -ExecutionPolicy bypass) and then executing the script (.\Update.ps1 -Verbose), the script runs perfectly (i.e. the file is written to excludes and deleted) and you can see the verbose output (writing and deleting).
If you run the following (similar to task scheduler) powershell.exe -ExecutionPolicy bypass -NoProfile -File "C:\Update.ps1" -Verbose, you can see the new script get executed but none of the steps afterwards will execute (i.e. no adding to excludes or removing the file or the verbose outputs).