Hi,
when you create a group and display it on your site the expected behavior is that each advert of the group is displayed with equal probability on each site reload. This means that if you visit your site 100 times, each advert in the group should be displayed roughly 33 times.
However, I noticed that this is not that happens on your site, because the site is cached by cloudflare.
A workaround would be:
configure your CDN caching such that the HTML is always generated by your wordspress and all the heavy network loads (such as images etc.) are still loaded from the CDN. This way you have a dynamic site structure while maintaining fast loading times.
