OData v4 (6.1.0) nested filter $ in $ expand

I have an asp.net 4.5 Web Api oData v4 service that works very well, but today I ran into the problem of nested $ filters in $ expand.

It says here

that OData V4 supports nested filters in $ expand. Request below the return People and all their trips named "Travel to the USA".

GET serviceRoot / People? $ expand = Trips ($ filter = Name eq 'Trip in US')

and it shows a good example of data that does just that.

There is also a coded example in the web API for oData v4 Docs here

I have an HTTP call:

serviceRoot/Languages?$expand=translations

      

        
        
        
      

    

which returns a list of languages ​​with their extended translations and I can filter the top level list with this:

serviceRoot/Languages?$expand=translations&$filter=isoLanguageShortName eq 'en'

      

        
        
        
      

    

However, I cannot filter the extended translations like this:

serviceRoot/Languages?$expand=translations($filter=languageName eq 'English')

      

        
        
        
      

    

This call seems to be the same as the one in the quote above and the effect should be the same as my data.

Does anyone know where I am going wrong? Do I need to set something in my ASP.NET code for this to work (for example, do we need to add MaxExpansionDepth to the EnableQueryAttribute to query deeper than two levels)?