Is this based on instance performance accepting the subscription, or is it a generalize Lenny bug where it doesn’t send it properly?
Lemmy federation, server to server, is having a number of problems. Comments and postings aren’t always getting copied over to all the servers who have subscribers. For over a week, Lemmy.ml has had regular nginx 500 error codes on the front page, sometimes you have to refresh 3 or 4 times to get a page to load.
Growing pains.
When subscribing to communities it occasionally says “Subscribe Pending”
Your specific issue is documented and I opened a fresh issue on it today: https://github.com/LemmyNet/lemmy/issues/3203
I have a couple pending subscription but they still show up in my subscribed list and I can interact with them fine so at least for me it’s just a visual bug.