Short links not works

I'm trying to create short link over channel manager. So, I'm going to channel manager, click on Edit Page, then click on Gear and then "URL and Navigation Manager".

I'm clicking on Sitemap section and then click on "Add New URL Design". Then I'm write short link, for example "about" and then I'm pointing it to 'content/about' page.

So, all by trail

Then save, going back to channel manager, Save & Publish.

When I'm trying to get by this link I'm getting ugly error page with totally confusing text
"Page not found!!!"

After some investigations I found that short link is not rendering as well. And when I add property to
hst:hst/hst:configurations/paintnite/hst:sitemap/<SHORT LINK>
+ hst:componentconfigurationid = hst:pages/contentpage

it works as need. So, I understood that this is internal error page and somehow it doesn't work. That's strange as it works on 7.9.5 version.