Why don't favorites & boosts federate from Mastodon on microblogs?

I've noticed that when I'm browsing microblogs on Kbin, I see very few favorites (upvotes) on posts even when there are tons when you look at them from Mastodon. For example, this post doesn't seem to have any favorites, but look at it from Mastodon, and you see over 120. In general, federation with Mastodon is really...