I had noticed that some cross-posted posts showed a different style of link for those cross-posts: some show it as a link under the title and header of the post but above the body, and some show the link (usually) in the body of the post. In addition, the cross-post links above the body are relative links (open in my home instance), but the ones inside the body are hard links (open in the source community’s home instance). Lastly, the links inside the body show only on one of the cross-posts, but the ones outside the body show on both cross-posts.
At first I thought that the second style, the one in the body that’s hard-linked and only on one of the posts, was due to the poster manually adding that link. However, over time I realized that that was not the case because it looked too consistent across different users.
I searched for a mention of this in this community and found this post about it: https://lemmy.zip/post/8016049 - unfortunately, there’s either something I’m still missing or that the explanation is missing.
Here’s an example post I happened to find that is linking to an external article’s URL, but has both styles of cross-post link. It’s a post linking to an article URL too: https://sh.itjust.works/post/64304718

Does anyone know how or why the two different styles of cross-post link get created?
Edit: I’m going to consider this solved. Here’s what I think is the likely solution based on all the comments and examples so far.
It appears that the dynamic, outer cross-post links (outside the body, under the title and post controls) get generated by the Lemmy server and that it seems to require that the OP have a URL that it links to in the title. Lemmy seems to use that URL to identify cross-posts. The hard-coded cross-post link inside the body seems to be generated by some client(s) or front-end(s). I asked someone who had a post containing one what they used and they said Alexandrite, so that may be one of the possible sources of this.
Thanks everyone.

That post does not have a link, the URL is how Lemmy connects the posts together, it just finds posts that are pointing to the same URL
Thank you. So you’re saying that the cross-post link that shows at the top, under the title and header, is cross-referenced by the destination article URL. That makes sense. But how about the hard-link in the body? What creates that, and under what circumstances? Going by what you said, I would think that it would be generated if someone cross-posted a post that did not link to an external URL, but then then that wouldn’t explain the one I linked in the OP, which has an article URL but has both styles of cross-post links.
the hard link in the body text is generated when there is body text in the original post
But the original post in the screenshot in the OP has no body text and yet has the hard-link in the body? Thanks for trying to help me understand, but I’m still not seeing the pattern.
It was edited in or written manually, the user can do it by hand if they wish
unless they’re using a weird frontend, it wouldn’t do that
I had thought manually added for a long time too, but then lately I’ve realized that the pattern is too perfectly consistent, across multiple users.
I’m leaning towards a weird front-end or app too, something that maybe implemented cross-posting before Lemmy’s native functionality. One clue I’ve received from someone who posted something like that is that they used Alexandrite, but I don’t have access to that to do some testing.