I was working with a user to help them navigate an app in Web App Builder. I noticed when they clicked features that the pop-up shows only the title bar, with all the other fields/attachments missing. It doesn't do this for me, and I've never seen this issue before.
User's pop-ups:

My pop-ups:

User did say they were using internet explorer, and I generally use chrome, but when I tried in IE the pop-ups still look normal.