Yeah I think I remember Vitor explaining that you automatically connect to the relays that other peoples notes are posted to or some shit like that (that's probably not what's happening at all and I've just made that up in my mind, but whatever).
I've encountered some issues with my feed since the new update, particularly with hashtags of mine being unfollowable, and a complete inability to filter the waves of insufferable dross coming out of that mostr bridge.