I believe that SQLPS is defaulting to a different provider than the PowerShell command line so if you change the following line:

$path = "\\Servername\SQLBackupsFromPROD"

to this:

$path = "FileSystem::\\Servername\SQLBackupsFromPROD"

then you are explicitly specifying Get-Item to retrieve from the file system.

Let me know how you get on.