kbin by default throws everything that isn't formatted like a kbin thread into "microblogs". For whatever reason that thread on beehaw had an issue so it got put in the microblog section. I saw a similar issue result when one beehaw user tried to include a hashtag in the title of their thread, breaking it for both lemmy users and kbin users (lemmy displayed it weird, kbin put it in microblog section).

threads are essentially "special" microblogs with extra info. Mastodon posts will show up usually under the microblog section, but sometimes may end up in a thread depending on the situation.

On a technical level, lemmy users, kbin users, and mastodon users can all see the same content, just formatted differently.

@ppptan

Correct. The post was associated with the magazine/community. It was created on kbin inside a magazine so it was associated with the magazine in the same way a Mastodon user could insert the community address in the Mastodon post and have their post show up in the Lemmy instance in the Community area.

What Kbin is doing differently is that it's accepting posts from the wider fediverse which was created on platforms "unaware" of communities or magazines. Lemmy ignores those unless they contain specific community addresses, but kbin doesn't and instead routes those based on hashtags or to the "random" magazine. You can see in the "random" magazine tons of microblog posts which don't seem to be related to anything or stand-alone posts.