I think (but can't prove) that it has something to do with the way that Android is caching the content. I solved it by reducing the amount of timeline items that were loaded per page and eliminated pretty much everything else for the mobile app home screen view.

I also installed Redis on my server to see if it improved caching and because it was a requirement for Pixelfed which I am also planning to install and serve.

Between these things and random luck, I haven't had the endless load circle for over a week now.