Workflow with Grouped File Items: Only the first is displayed in the workflow preview

I have a workflow batch which contains 3 PDF files and 1 image (trying to publish the "Publications" section while the mandatory lang is blocking content on this page).

When you access to the preview of the workflow in the workflow dashboard, it only lists one single file. This is confusing for the reviewer as he belives he is only validating a single file but if he checks in the "Publication infos" tab later on in the process, he can see that there are more documents than originally mentioned.