Overlapping images in Gallery

The rtMedia Gallery created with the shortcode, [rtmedia_gallery global="true" media_type="photo"], isn’t rendering correctly on our site. The last item in the resulting Masonry grid overlaps with the item directly above it. Simply hiding the last item isn’t a solution, because the grid height resizes itself accordingly so that the last image always overlaps.

Here is the link to our gallery: Gallery

Any insight would be appreciated!