Oh, I just assumed it would work. But indeed it does not work in the way you described (and that's how it works on kbin as well). I was curious and did some searching. I stumbled upon this thread: https://lemmy.world/post/225841 and apparently you need to paste the whole URL from kbin in the search bar and then it shows up (I tested it on a lemmy instance and it seemed to work).
Edit: And it shows that federation does not always work great. Since your instance had 0 replies but that instance had replies and the correct one as well. Didn't notice it was the same question/post until after posting this.
Thats ok, happens all the time ^^
At least we both now Know what to Do and hopefully in a couple of month lemmy will be better federating with kbin. Right now we are all "Pioneers"