So, to explain in more detail: I read about a new community on newcommunities and I decided to search for it so that it started federating with Kbin.
However, when I visit the community on lemmy.world, there are already 32 posts from before the community became visible on kbin, but I can only see the posts that were made after I “discovered” the community on Kbin.
I just tested it with my account on lemmy.world, and the posts do indeed show up on Kbin now.
That’s really good to know. Thank you so much for the explanation!
Interesting, it seems to work the same way between Lemmy instances. It would be nice if I could force a more thorough federation, but it’s good to see most content will eventually come through on its own time.