I just noticed that my active and hot are 3 days old, it looks like this server is being hit with this bug where the hot calculator dies. Currently, there are fixes in the works and it may be worth cherry picking them or restarting the server during a down time until the fixes make it into the next release.
Unfortunately, we're stuck with the bug until we upgrade to a version without it. Restarting has been suggested, but the problem with that is that the outbound queue is held in RAM, so it gets lost with a restart.
We'll upgrade our version as soon as humanly possible
Yep :/ for any readers here is the issue in github.