we had a lot of date specific background tasks that run. one day one of the major tasks were not doing anything at all. check the builds in jenkins, was being triggered at 8pm as designed , but no output or errors, just success. eventually found out that someone changed the timezone on the remote host executing the job, so the job was infact running in the future where no events existed! needless to say was a simple fix! and mow I use NTP for everything