I’m not sure if this is something going wrong, or just how Mastodon works.
Anywho, when I go to Communities - Subscribed and click through to this one: https://lemmy.nz/c/rugby@sh.itjust.works
There are posts that I think are there that don’t show up in that view, eg: https://lemmy.nz/post/1077020
The only reason I know that post exists is because it does show up if I just go to https://lemmy.nz/ so i’m guessing it shows in the Subscribed Posts section, but if it isn’t there then i’d be missing the post entirely I guess.
Being a cross post shouldn’t matter. It’s probably some weird lemmy issue, hopefully it will get solved over time. I’m not sure if there’s much we can do in the meantime, but I suggested messaging a mod as they may have their own support community they can ask on.