Strange behavior with Divi
I discovered this by accident:
I am using the free version and I managed to display the category slider (layout 1) on the main shop page by editing the page (not with cornerstone) and adding the shortcode for the Root parent category in the text tab of the editor. I was trying to display the Subcategories in a slider (layout #1) on each category page, but when I tried the same method (by editing the "product category" and adding the shortcode for that category parent, it showed up double! So, I deleted the shortcode, updated the page and it still displayed the subcategories, but this time only once!
You can see the behavior here:
I am still trying to figure this out, but right now it works and I don't want to break it.