EVA fields not displayed field groups

Problem/Motivation

I use EVA (Entity Views Attachment) fields extensively together with Node References. Before I started using field groups the EVA fields used to be displayed with the nodes which they referenced.

I have tried using various types of field groups. I have only managed to display the EVA fields with Accordion Group/Item and Vertical Tabs Group/Item. With Fieldset, the EVA fields are not displayed and are often not even shown under the Manage Display tab.

Is this a feature or a bug?

Steve