Uploading file through script not working

Product: PowerShell Universal
Version: 3.10.1

[CmdletBinding()]
param (
    [Parameter(HelpMessage = "CSV with the following headers [DriveLetter] and [path]")]
    [File]
    $File
)

return $file

docs.powershelluniversal.com
I would expect the following script (according to the docs) to have some content but I keep getting the following error. I am running PSU as a service on my local machine.

[error] Could not find file 'C:\WINDOWS\SystemTemp\psufile.4.bin'. 

After getting this to work, I’d also like to use the New-UDForm -Script (Get-PSUScript -Name 'upload.ps1' -Integrated) -OutputType 'Table' cmdlet on a dashboard, but it looks like the file upload param is not working as its showing up as an input field.