Slides move too fast when return from another tab

Hi, I installed Full Screen (Page) Background Image Slideshow plugin. Everything is fine. But when I change the tab in my browser and return to this website after some time, the images slide very fast. At that moment it looks like everything is messed up. but after refreshing the tab it works fine. Here is my site:

https://www.ads-software.com/plugins/full-screen-page-background-image-slideshow/