Additional images not displaying – how to fix?

When I upload 3 images to my classifieds ad post, only 1 image appears.

I created a listing package that allows up to 3 uploads.

When I edit the listing, I see a star icon next to the 2 non-displaying images with the tooltip “Display Image” (as in attached screenshot).

I click on this star icon next to each image and they disappear and I save the post. When I refresh the page listing, I still only see the one image.

When I edit the post again, I again see the stars appearing next to the two non-displaying images.

How can this be fixed?