I just checked this and you are right I can see posts from a Subscribe Pending community showing up. Hopefully, it gets fixed soon to save confusion. Thanks for the tip :)
@Nutomic I've noticed this exists for all federated subscribes, even ones that happened in the past.
I am having a big issue with external communities not subscribing. Many are stuck in "Subscribe Pending". I found a link to a related GitHub issue that might be helpful for Tom to look at. Unsubscribing and resubscribing is not working on the Feddit instance.