@malte@forum.fedi.dk yes, because you are using NodeBB. It will send the activity to as many people as it possibly can, who have any relation to the topic.

julian@community.nodebb.org
Posts
-
Moving fediverse thread into forum: Handling replies -
Moving fediverse thread into forum: Handling replies -
Moving fediverse thread into forum: Handling replies@niels @fedilab@piaille.fr likely uses reply tree traversal.
-
Moving fediverse thread into forum: Handling replies@Kichae interesting! I'll have to test that flow. I've never tried moving a Lemmy topic in to a category and seeing whether future replies federate in properly.
-
Moving fediverse thread into forum: Handling replies@niels @Kichae @eeeee what specifically you're asking for here is a way to retrieve the entire conversation, all branches of it, for the full context.
This is not something ActivityPub can do currently by design. However I am working with a number of separate implementors to establish something like this. You can see the progress of our efforts here:
The state of conversational contexts (February 2025)
A conversational context is what the ForumWG uses to describe what you might see as a reply tree or comment thread. One of the short-to-medium term goals of ...
NodeBB Community (community.nodebb.org)
This is already working in the wild. If you attempt to pull any post from NodeBB, you will get the entire topic, including remote replies.
Mastodon is separately working on something called "reply tree traversal", which is something that will also work but is an approach I feel is fraught with reliability issues.