A second issue I have since many versions of PI 3.0 and 3.1 is that after a reboot (or patch installation) the System Jobs aren't working anymore.
The "Next Start Time" then is in the past and they wont ever get started again. Affects nearly all of the "Wireless Monitoring" jobs, but also affects others. I have then to select the ones with a "Next Start Time" in the past, pause the series, select them again, resume the series. This works, until the next reboot or patch installation.
It would be great if this could be fixed.
Do you also have this in your installations?
Maybe it's a time-zone issue? Using CET here and it's synced by NTP.