There is a bug in 0.17.4 that stops front pages from updating shortly after the server is restarted, thus resulting in βhotβ and "active" showing stale posts.
I have fixed this issue on https://lemm.ee already, you can check our front page to see fresh posts. The fix will soon land in the main Lemmy codebase as well so other instances can take advantage, you can track the issue here: https://github.com/LemmyNet/lemmy/issues/3076
I have also advised other instance admins that regularly restarting their Lemmy server will work as a band-aid workaround until the proper fix is released, so some admins have already implemented this in order to get their post rankings working again, but the proper fix will come in the next release of Lemmy.