In the last past days, at least 2 occurrences of the following happened:
At some point, passive checks all start returning:
WARNING: passive check is awol
And downtime actions doesn't seem to no longer take effect (the command is sent and is successful, but the service doesn't effectively get its scheduled downtime).
Checks/alerting in general continue to work as intended.
Last time this happened was 2018-06-04T07:30. A restart seems to fix both issues, at least temporarily. Suspecting some kind of malfunction that gets reseted, but not fixed, on restart, but builds up until it happens again.