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.
yes this happens, but it resolves itself over time, and the posts will show up within a few hours or days. this happened to me on a few of my mags i federated between kbin/lemmy, eventually all the posts showed up 👍🏼