First Share badge is here.
The same situations with the other sharing badges.
The bug is still here.
Thank you, @julienkay, for the solution, but it doesn’t work as intended, @Brach_Unity
You have to append
?u=<your-username>
to the url of a post.
For example
https://discussions.unity.com/t/ar-unity-developer-10-years-of-experience/1514102?u=makaka-org
P.S. It doesn’t work for all suggested sharing websites because my 1st post was ignored. But the second counted.