I went down this rabbit hole this morning. There was a bug pre version 0.18.0 which caused this when subscribing to a federated community. If you go through and unsubscribe and resubscribe this should fix the issue. I did this myself and it fixed all except one which, unfortunately, is from lemmy.world. I am wondering if their instance is having an issue or if maybe they're on an older Lemmy release which is causing an issue.
sdfpubnix
Fans of SDF
I only have this problem with lemmy.world as well. Strange, since they've upgraded to 0.18.
Both of the ~~subs~~ communities I have this problem with are on lemmy.ml. But one of my other lemmy.ml subscriptions works fine as does lemmy.world. 🤷
I think it's related to overloaded instances. I got up real early (CEST) when Americans are mostly asleep, and unsubscribed + resubscribed to the "pending" lemmy.world communities, and now I'm properly subscribed. This did not work during "prime time" yesterday.
This worked for me for a couple of communities that were stuck in the 'pending' state.
I have it on many subs, on lemmy.world and lemmy.ml, it looks like they do subscribe and it's simply an issue with latency on return calls/sync/federation.
I've noted that I assumed it was for manual review or a hiccup in the federation that would eventually clear itself I'll have to check those communities later to see if they are still pending
Sometimes I'd have to wait minutes, but I'd give up after a day. I'd just leave it pending and then the next day cancel the pending and try again. Eventually they all got subscribed. 🤷