Not sure how their curation is set up exactly, all I know is they leave gifs with this account when they upvote the posts (I think): https://peakd.com/@steemmonsters/comments
but since many of them land late it leaves room for others to predict which posts are going to get upvoted. Who knows if those predictions are only a guessing game but metrics show that they're pretty good at it to the point of taking 50% of the curation rewards of one of our biggest projects in the ecosystem.
Solution is to simply have more curators actively curate content as it's coming out rather than try and play catch-up later. Voting on posts purposely late also doesn't make a lot of sense since they'd want good SPL posts to get hot/trending attention to bring new users to the game.
The votes seem to land as the comment is placed so I'm guessing the curators have posting authority to cast the votes. If other curation projects can easily get to most posts before the 24h window I don't see why they can't.