For my case, the WFEs will not run the query component, and therefore they don't appear anywhere in the XML input. The script therefore does not recognise them as a SharePoint server.
I worked around this by adding my own custom config file and overriding the Get-FarmServers function to get the server names from the default config file, plus my custom config file.
I worked around this by adding my own custom config file and overriding the Get-FarmServers function to get the server names from the default config file, plus my custom config file.