Mike,
Thanks for chiming in. I have pulled my nano router off the controllers usb port. (Ray had suggested that I power them from the OS 3 usb port. I was not a big fan of wifi only). It is now powered separately but from the same power source. The router maintains an up time and does not show a loss of service. When I had it plugged in to the controller it would reset as well.
My setups are unique as I use ubiquity Line of site radios in the field to supply internet to these units. I have over 15 of the 2.3-2.1 units deployed without issue. This is the first 3.0 that I have deployed with the same setups and it has been a problem. I have done my best trying to isolate the issue. I found another thread where someone reported rebooting but it was on a 2.3 DC unit. Which I have one of those and it appears to be working without issue.
As a backup I am also using a Levington smart switch as a fall over now so my lights stay on, but I 30 irrigation stations that are being disruptive.
Once it get to a point where I can no longer view the logs, I have to reset to defaults and reprogram. Once this is done the rebooting appears to only happen at night when the lights are on and possibly when the stations are running.
It is frustrating but I am trying to solve the problem and come up with proper diagnosing steps to be able to quickly resolve issues in the future.