Shouldn’t copied and pasted links to individual posts have a preview (much like how a quote looks like)? Mine only shows a URL line, and I’m not sure what happened.
It used to work in 2018, but it doesn’t work anymore when I’m trying it in a new post (although the old posts with links to posts show a preview just fine).
Has anyone encountered this before?
Hello!
If you paste the link without living any space in front of the link, it should appear as a preview, something like that:
If you do leave space, it will appear like that:
Copying link to post into a reply does not show preview
It depends on the source of the post.
You can’t link something from a category with restricted permissions, that would bypass the security placed around the topics/posts.
Thank you Stephen!
And this includes posts within the same category? That seems weird - they would have the same permissions though, wouldn’t they?
Sure but that still assumes that some degree of permission enumeration is going on, beyond checking if the source topic is public.
Thanks Thomas, this is helpful, but apparently it can’t work in reverse when it comes to categories that are made private! 
Got it, thanks so much @Stephen! It’s a shame that it doesn’t work within the same private categories/restrictions.