I’ve just checked on kbin and the link works just fine. Kbin doesn’t display the full link, but when you click it on the website it works.
Are you using an app to browse kbin? In that case it’s your app that’s not doing it correctly. Possibly kbin doesn’t give it the infomration, or maybe it just reads the text of the link and misuses that.
Either way, the problem is nothing to do with lemmy. However lemmy apps have their own little bugs to work out (eg instance agnostic links from v0.18) so we’re all in the same boat of fedeverse development.