Some federated communities not appearing in search

Hey everyone :) First ever post in the metav-....I mean fediverse!! (damn you, Zucc's PR department)

Jokes aside, this is so exciting and I can't wait to see what lemmy will look like in a year or two. I like to believe that I'll be still here and the explicit long-term commitment of this instance is very motivating!

Now to the problem in the title: I hope I don't make a fool out of myself but I haven't read anyone mentioning this while looking through the latest posts in this community. While searching for communities to subscribe to, I noticed that some don't appear in the search results when searching from the lemm.ee instance. Specifically I was trying to subscribe to the vitahacks@lemmy.ml community or the skychildrenoflight@lemmy.world community.

Am I alone? Am I doing something wrong? Did I miss something? Every help is appreciated.