WMI/CIM: Unable to access class

Question

I have a non-standard WMI namespace/class I'm trying to access, but am unable to by conventional means. I can see the class when I use the -List parameter, and can assign/access the class when using -List | Where-Object Name -eq 'Class', but am unable to access it via Get-WmiObject -Namespace 'ROOT\Novadigm' -Class 'NVD_Agent' (returns nothing)

Works:

PS C:\> GWMI -Namespace 'ROOT\Novadigm' -List | ? Name -eq NVD_Agent


  Namespace: ROOT\Novadigm

Name          Methods                 Properties
----          -------                 ----------
NVD_Agent     {AddInstance, Del...    {}


PS C:\> Get-CimClass -ClassName 'NVD_Agent' -Namespace 'ROOT\Novadigm'


  Namespace: ROOT/Novadigm

CimClassName  CimClassMethods         CimClassProperties
----          -------                 ----------
NVD_Agent     {AddInstance, Del...    {}

Nada:

PS C:\> GWMI -Namespace 'ROOT\Novadigm' -Class 'NVD_Agent'
PS C:\>
PS C:\> Get-CimInstance -Namespace 'ROOT\Novadigm' -Class 'NVD_Agent'
PS C:\>

Question: Why is this happening? How can I get it to work by using standard syntax without passing it through Where-Object?