On kbin.social, posts featuring Lemmy posts receive more upvotes, and it defaults to sorting by "Hot content." For a more accurate representation, sorting by "Active" or "Newest" or */sub is recommended. On the other hand, karab.in primarily federates with Polish Mastodon instances, and szmer.info is not as popular, hence the difference.
Nothing will escape you, as usual. I'm adding it to the todo list, even though I was planning to skip filters for now, but... it's actually a pretty nice feature.
These points are not a priority, but relatively easy to achieve. They will gradually appear on the instance in between working on significant things. It's worth following https://kbin.social/m/kbinDevlog
This may be more noticeable on weaker internet connections. There is also browser-side caching, so it may not work perfectly everywhere. Currently, this is an experimental version. For the server, it's marginally better, but there are no significant differences, is more about the user experience.