Subscribing to a community from another instance always shows "Subscribe Pending". Is this a bug?

It is a known bug. I tried to find the source but was not able to to find it again. From what I recall, when it says "Subscribe Pending" you are subscribed, it's just a display issue and should be fixed next release. I'll update if I can find the source

Edit: still not the source I was remembering, but here is an open GitHub issue for this: https://github.com/LemmyNet/lemmy-ui/issues/1315

I think it is a bug and here's why

I have setup a lemmy instance to understand how it works and hopefully contribute something meaningful

My instance has 2 users, both are subscribed to the same cross-instance community, but only one is showing Subscribe Pending even if I un-sub and re-sub

I am not aware of any approval system to subscribe to a community, so I believe the approval was received the community instance, but the "accept" response data was missed / dropped when returning to your host instance

None of my accounts are on lemmy.ml, and this only seems to happen for me when I subscribe to lemmy.ml communities, so I'd bet lemmy.ml is just struggling with the increased traffic