Shared With us Functionality SharePoint Group

I am search for a guide how Shared With Us in SharePoint Online works. You can share a folder with another SharePoint site. Once you click on documents you get the option Shared With Us. 

 

But when I share a folder it does not appear to show up in the Shared With us. In the site that i invited.

Is there a issue here? TimerJob? etc.

 

How does it work? Any ideas?