Infinite scroll occasionally has issues for me on lemmy.world. Seems to always clear up after an hour or two so I have always assumed it is maintenance/issues on the instance side.

Restart the app, logout+login again, and if it still persists after a few hours it is likely a configuration issue with your instance. Maybe make an account on another instance to rule that out.

I just made a post in this community with a bug saying the same thing. I'm new to Boost and sh.itjust.works/instances, so not sure how to test further to fault-find either way.

Open the sidebar and tap your username, you can add accounts from other instances