I seem to be experiencing similar intermittent drop outs of my AC version controller. It’s powered from a GFCI outlet, which very occasionally trips. This happened whilst we were away and I missed 3 days of watering, so I set up notifications in my HomeSeer home automation system to send me Pushover messages when the OS controller device goes offline. I quickly discovered that it was going offline relatively frequently when the GFCI was still live – the GFCI hasn’t tripped since we were away in mid August. I added another notification to tell me when the controller comes back online and for how long it’s been offline.
It’s dropping out about 5-7 times a day and reconnecting after ~20mins each time.
I haven’t been home and awake when it’s dropped out yet, so haven’t been able to check the controller display and the ethernet port light activity, but I should be able to see that tonight.
HW Version: 2.3 – AC – purchased in July 2016
Firmware: 2.1.6 (1)
1 x zone expansion board