Let’s say we have a single post template with infinite scroll and older posts (full posts) are loaded right below. When the user scrolls to the 2nd post, the URL should be updated to ensure it appears in the browser’s history and so that the user can grab it from the address bar. The permalink should match that of the currently visible post.
That is how news/blog websites that have this functionality implement it. Otherwise the infinite scroll on single posts is kind of pointless imo.
Has anyone done this in a bricks website?
Another feature that would be nice to have is stopping the infinite scroll after x number of loaded posts/pages and replace it with load more button, so that the user doesn’t “chase” the footer. Infinite scroll that is actually infinite 
can by annoying in some cases and having a fixed footer isn’t ideal.