@Ferk Interesting. I have checked the link from you, to see it from their perspective. And sure enough that won't show me a link too, BUT... The guy from kglitch.social has a link. What I think happening is following: Because I respond to the guy in the same instance kbin.social, it won't put the entire name. I know this from Mastodon, where if we are in the same instance, I don't need to put the instance id to tag someone. And because the guy from kglitch is not in the same instance, it will automatically create a full id reference, which every instance render as a link.
Hopefully I could explain what I think is happening. Maybe it is not an issue with kglitch itself, but how Kbin works.