This doesn't seem like it has anything to do with KBIN, and is just a link-to-a-link, including the now-broken hashtag.
The sequence of events:
BBC launches a Mastodon instance at social.bbc
here
A user from kbin.projectsegfau.lt
posts the news to kbin.social
Another user from kbin.social
cross-posts the Project-SF-post-to-kbin.social
here