Some of that is servers not keeping up with load or smashing into various other scaling problems. I've seen posts on both the Lemmy and kbin side with people trying to work load issues out, but if I look at either kbin.social or lemmy.world, the largest kbin and lemmy instances right now, I see a bunch of activity on each instance that hasn't yet propagated over to the other.
That being said, it beats early Reddit, where the whole shebang would go down for a day or two sometimes as they tried to scale up. At least here there are always more working instances that one can fall over to.