Why does an MSI downloaded with Invoke-WebRequest fail to install even though it matches the manual download?

I'm trying to automate downloading the latest PowerShell Windows x64 MSI installer with PowerShell. Invoke-WebRequest completes successfully, but launching the downloaded file produces: "This installation package could not be opened. Verify that the package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer package."

The strange part is that the downloaded file appears identical to the one obtained manually from the release page. Comparing the files byte-for-byte shows no differences, and their SHA-256 hashes match as well.

The script currently obtains release metadata, selects an asset matching `*-win*x64.msi`, extracts the filename, and saves the asset with Invoke-WebRequest:

`$repository = 'PowerShell/PowerShell'`
`$fileNamePattern = '*-win*x64.msi'`
`$downloadPath = 'C:Temp'`
`$releasesUri = "https://api.github.com/repos/$repository/releases/latest"`
`$downloadUrl = ((Invoke-RestMethod -Method Get -Uri $releasesUri).assets | Where-Object Name -Like $fileNamePattern).browser_download_url`
`$fileName = [System.IO.Path]::GetFileName($downloadUrl)`
`$destination = Join-Path $downloadPath $fileName`
`Invoke-WebRequest -Uri $downloadUrl -OutFile $destination`

Unblocking the file, running it elevated, double-clicking it, and invoking `msiexec /i` all produce the same result. What else could cause Windows Installer to reject this file when the downloaded and manually downloaded files have matching contents?