Two services that are very interoperable (because kbin is designed to be, specifically able to bring in microblogging content while lemmy can't) and still have problems. Did you know boosts are what make comments appear higher on kbin while favorites work that way on Lemmy? That's the sort of thing I'm taking about. Every implimentation of activitypub kind of makes its own rules on what tokens mean and if you want to be compatible, you have to change your service as they change theirs (which is what happened, lemmy changed and kbin hasn't gotten around to it yet since it's not a big priority).