Smush Shows a Negative number of images

On this site, we've run Smush for a while now and decided to enable the "super smush" option to try and get our images to fit Google's guidelines. I noticed, just before enabling the option, that the images showed a negative number (I thought that was odd). I went ahead and super-smushed and, sure enough, the number is still negative (see screenshot). My smushed attachements are now larger than the files in the site. We're also getting gripes from Google still which makes me wonder if there isn't something wrong or some setting I have set wrong. Any help is appreciated.