Every several days, active checks seem to get stuck, while the date shown for "Next Scheduled Active Check" is in the past (days, hours, in the past). I can only make it go away by doing a full cleanup of nagios data, but that is not feasible on the long term. A simple restart of the nagios service fixes nothing.
Both machines run ntpd, so the time is always in sync, that should not be a problem.
Any ideeas? I'm seriously thinking of dropping nagios in favor of zabbix, or similar