Memmy - An iOS client for Lemmy

I’ve noticed that I can’t subscribe to certain communities. For example if I search for Memmy and click on subscribe, the heart goes from an outline to a filled heart and I get a notification that I subscribed to memmy.

However, if I exit the Memmy community page and then re-enter, the heart is back to just an outline as if I’m not subscribed and it doesn’t show up in my subscribed communities.

Not sure if it’s a Memmy problem or a federation problem. My account is through Lemmy.world, have consistent problems with Beehaw and Memmy is on Lemmy.ml.