Why do I see posts/comments from beehaw users on communities outside lemmy.world and beehaw.org?
That’s because the “true” version of those posts is outside beehaw. So we get updates from those posts. And lemmy.world didn’t defederate beehaw, so posts/comments from beehaw users can still come to versions hosted on lemmy.world.
The reverse is not true. Because beehaw defederate lemmy.world, any post/comment from a lemmy.world users will NOT be sent to the beehaw version of the post.
Third instance communities
Finally, we have the example of communities that are on instances that have not been defederated by beehaw.org.
We can see all three of these versions look pretty similar. That’s because for the most part they are. We are identical with lemmy.ml, as lemmy.ml hosts the “true” version, and we get all updates from the “true” version. Beehaw.org will not get posts/comments from us, so beehaw actually doesn’t have the most “true” version of this community.
Translated into the current context:
beehaw.org = your instance, which defederates from Threads
lemmy.world = Threads (sorry folks, just to eplain the mechanics)
lemmy.ml = another instance, which is federated with both, your instance and Threads
Conclusions:
You wont see posts or commens from Threads users in that remote community. You also won’t see reactions to those activities from anyone, anywhere. It’s as if comment chains started by Threads users don’t exist.
Threads will not see posts and comments from you, even if done in communities from instances which are federated with Threads.