Just joined Lemmy today. From what I understand, there are different Lemmy instances that host different communities. I supposed that to interact in a community hosted in a certain instance, I would need to create an account for that instance. Ended up creating 10 different accounts.
I'm not aware of the problems, so I can't make such a post. Looking at this now and searching by URL for magazines on kbin and communities on lemmy instances both seem to work as expected, so I can't reproduce what you're seeing.
I am aware of issues with lemmy.ml, searching for communities that are hosted on that server will often fail the first few times, and subscribing to communities that are hosted on that server often shows that subscriptions are "pending," so if that's where you are searching for communities I can see why it'd be an issue. Federation is a two-way street, so if lemmy.one can't fetch remote data then it won't work, but I've seen many other reports of people subscribing to remote communities just fine, so I don't think there's any issues we're seeing on our end.
I had the same issue though only on jerboa. The website search works fine.