GET Related Records Data does not respond to fields Query Parameter

GET Related Records Data does not respond to fields Query Parameter

I am trying to get a list of emails linked to a Contact, using the GET Related Records Data API call.  It works if I want all the record fields.  However, although the V2 guide specifies a "fields" Query Parameter, this is ignored.  So even though I use a URL in the form https://www.zohoapis.eu/bigin/v2/Contacts/{contact_record_ID}/Emails?fields=Subject I get all the fields, not just the Subject.  I notice that the V1 guide does not support a Query Parameter.  Is V2 actually working as specified?