lemmy.world shows this place has 55 subscribers but struggles to load, this post didn't show. lemmy.ml shows and loads this place with 6 subscribers and I can see this post.

So I will give you the info that I have come across over the last couple months. At least one user from instance A (e.g. Lemmy.ca) must be subscribed to a community on instance B (e.g. Fanaticus.social) for instance A to federate that particular community’s future posts/comments. This does not mean that prior posts/comments will federate. What should happen is that future posts/comments for that particular community should be visible for any user from instance A going forward. Other communities in instance B will not necessarily federate and will each require at least one subscriber from instance A for future posts/comments to show up.

The only real solution at this stage is to make an account on different instances specifically to subscribe to the main communities on the target instance so that users from those instances will have “proper” federation.

Edit: Tagging @[email protected] for visibility on that account as well.

And from fanaticus: yes, this post appears. So strange!