The way Lemmy federation works, is a logged in user on an instance can search for a community and it will pull a handful of posts for the front page (if I remember rightly, it's only posts no comments or votes).
That's a "pull", requesting the content. The instance will get no further posts except from a "push". A push happens when a user subscribes to a community on a remote instance, then that community adds the instance of the subscriber to its list of places to send new content. Once there is a subscriber, any new content (posts, comments, votes) get sent to that instance. The bot doesn't do anything except subscribe.
That first "pull" federation doesn't really count. Communities aren't really visible to users unless they are showing in feeds, and to do that they need new content and votes.
I'm heading to bed but will pop a post in the lemmy-federate community asking for more info on what might be going wrong.