Featured Image on pro does not display an image in my Encyclopedia entry

On my /encyclopedia page, all the other entries were from when I was first testing the free version of this plugin. On those posts, I manually added the image to the individual encyclopedia posts and had, until now, assumed that featured images would be displayed in my encyclopedia entries the same way they are in other posts on my site after I upgraded this plugin. Unfortunately, that is not the case and I have been unable to figure out what is preventing them from displaying as they should.

Ideally, I wanted (still want) thumbnail for each entry on /encyclopedia and, of course, a full sized image for each “encyclopedia” post type.

For regular posts, I don’t add any image other than the featured image, resulting in a thumbnail on the main blog feed for posts and the requisite full sized image on the individual post.

So I can’t figure out what’s different here with “encyclopedia” or if it’s something I’ve overlooked. Can you help?

The page I need help with: [log in to see the link]