@mpalmer thanks a lot for your answer! Definitely you got more technical skills.
I read about homograph attacks and it sounds to me a serious problem. But, I still can’t understand your point.
If this is not URL, than why, when I press
share button, discourse gives me this non url link? And why, when I put this non url into my browser it works completely fine (checked firefox and chrome)?
Maybe there is a way to disable preview for this kind of links, and enable clickable feature? Maybe some related options in admin panel exists?
Btw: found some workaround. When I post link inside the same discourse site, then I can simply remove domain name and use relative link. It works fine, but still does not satisfies many users.