I had the same issue browsing a lemmy.world community from kbin.social, looks empty to me from kbin except for this message:

The magazine from the federated server may be incomplete. Browse more on the original instance.

So I checked the original instance and there were already some threads there, then I created a new thread from kbin and it worked, it appears on both kbin and lemmy, but from kbin I still can only see my own thread, not the rest.

Oh well, I guess it's a matter of time, @ernest is working really hard to fix everything and so far apart from a couple of things it has been a pretty smooth experience for me.