Not sure if this is the right community to post.

I’m very new to Lemmy and Kbin, coming from Reddit. I have been joining many communities on Lemmy. I noticed today that Kbin was federating, so it should be possible to subscribe to their magazines from lemmy.world. I did that for their large ones. But it only shows two or three posts. Is it a matter if waiting for the others to be populated, or are they not compatible?