Hi,
That's normal. It's not particularily the infinite scroll that doesn't work with random items.
It's actually the pagination which is disabled completely.
So there is only one page of elements, and thus no pagination, and thus, no infinite scroll.
That's because the random items are done per request.
If we were activating the pagination, there would be an unlimited number of pages, and you would be products several times on different pages as each time a page of the listing would be displayed, it would select a random number of products amongst all the products of the listing.