Set-SCPItem : Cannot process argument because the value of argument "path" is null

Hello all,
With the command
Set-SCPItem -Path ".\file" -Destination "/home/pi/" -ComputerName $ComputerName -KeyFile $KeyFile -Credential $Credential -Port 2222
I always get Cannot process argument because the value of argument "path" is null. Change the value of argument "path" to a non-null value.

My private key has a password and I coded it like this :

$keyPassphrase = "aaaaaa"
$KeyFile = "C:\Users\USER\.ssh\id_rsa" 
$secKeyPassphrase = ConvertTo-SecureString $keyPassphrase -AsPlainText -Force
$Credential = New-Object System.Management.Automation.PSCredential ($User, $secKeyPassphrase) 

Same when Keyfile has no password.
Same when using "Set-SCPFile" which don't have this paramter "Path"...
I'm sure the error occurs at this command and not anywhere else.

PoshSSH version 2.2 (Install with Install-Module -Name Posh-SSH) ; Local OS: W10 ; remote OS: Raspbian 9.9 ; PS version: 5.1.18362.145 build 10.0.18362.145 ; SSH version on remote device: Open SSH_7.4p1

Start by reproducing the exact Set-SCPItem command with the supplied PowerShell 5.1 and Posh-SSH 2.2 details, then compare it with Set-SCPFile. Trace where the null path error is raised and verify how -Path, -Destination, -KeyFile, and -Credential are handled. Done means the command no longer rejects a valid local path, including when the key has or lacks a passphrase.