[Plugin: Twitter Mentions As Comments] Not finding "shortlink" version of URL

I have two different types of links back to my blog, they look like this:

https://schjetne.net/2012/08/31/putting-the-pieces-together/
and
https://schjetne.net/841

I’d like this plugin to find the second one, the shortlink. I thought I’d only have to define that that’s the shortlink in the header, but it’s not.

Any ideas how to mend this?

Thanks in advance!

https://www.ads-software.com/extend/plugins/twitter-mentions-as-comments/