I still see things from 7 days ago at the top when I sort by “active” while other posts have much more activity and are newer. “hot” is the same thing with most posts from 5 days ago.
On https://lemmy.ml/ and https://lemmy.world/ it seems like sorting by “active” is working, there are posts from around 3h ago that have 100 upvotes so that I would consider “active”.
I’ve said this elsewhere, but I’ve been sorting by new and going to the second page to avoid post bursting. Just refresh every once in a while for new posts to look at. Lemmy v0.18 should be out soon and will hopefully fix these bugs