Image Gallery will not display in Collapsible section

We are creating an informational site. Author has several collapsible sections. Inside one of these, she wanted to add an Image Gallery. After uploading images from her desktop, the Gallery looks fine in publish mode. After republishing, the gallery completely disappears, leaving only a large blank space. (see images below). We've tried deleting and re-adding the gallery, different browsers, different pictures, refreshing the page, clearing the cache and having others add the gallery without any change. We're at a bit of a loss. Can anyone provide some clarity?

In edit mode before publishing.After republishing