I'm guessing all the shitposts that don't load on 196@blahaj for me are from users on overloaded instances, because when I post there, the image is uploaded to my home instance and referenced in that post on the 'foreign' instance. Plenty of error placeholders there lately. Concerning your question: I think a community gets delayed into your feed if its server federates slowly or not at all until it is up again. I see sudden post batches appear in my feed sometimes and unseen posts from hours ago.

They're still up on federated instances. You can even comments on them, and it'll get synced once the original instance back online.