Running the above cmdlet and passing what is apparently the only required parameter of name, results in the above obscure error. It refers to a parameter that doesn’t appear to exist for the cmdlet. There is also the -migration parameter that looks for a object array that no other HCX cmdlet provides.
Long story short, informed VMware, they are going to fix the cmdlets and their documentation. In the meantime, here are some examples that VMware’s GSS shared to be able to use the New-HCXMobilityGroup cmdlet.
Here is the code: