I went through all of the SG Optimizer settings and seemed to have solved this. I turned off Combine JavaScript files, Defer Render-blocking JS. I also turned off all of the Image optimization. Not sure which specifically fixed the issue, but seems to be working.
I am having the same issue. The portfolio disappeared from my site. You could see there were still hover effects, but the images were gone. I tried reapplying the portfolio using shortcode instead of placing the element, but that did not work. Going through plugins, it appears that SG Optimizer was causing the conflict. SG Optimizer is provided by SiteGround to help keep the site light. Is there a solution to this?