This federation concept does not work as expected for me. If I understand correctly, I can access a community from mastodon, kbin and others. But In practice I get a lot of 404 errors.
Also the search functionality seems really broken when you want to search a community from another instance, sometimes it's in the results and sometimes it's not. Is there a cache of some kind or a really long delay when a community is new?
I'm having this exact same experience. At least I know it's not me. I'm having it with links not associated with Kbin too, so that isn't the entire problem.
I'm not 100% sure but I think as of now kbin users can view lemmy instances, but lemmy users can't see kbin posts.
Unfortunate but hopefully they implement the feature soon.
As for search, yeah if a community is being fetched for the first time in any instance, it takes a few seconds to fetch all the info. Subsequent times search will show it instant as its already stored in local dB.