You can’t. If @mistersteve and @scout both saw their likes drop to 57 and 70 from higher numbers while this thread was running I can only assume some jokers were adding likes then unliking them quickly after and they just saw in that brief period. Otherwise I would assumed when users are deleted their likes also leave the system so It’s natural that some of the really popular older posts would no longer have the numbers they once did.
If it’s not anything like that then I’ve absolutely no idea, unless there are actually a huge number of ‘spambot’ joiners designed for Discourse that come onto the site and they start by liking posts under these popular categories but shortly thereafter the automated system finds and deletes them?