If I’m not mistaken, the firmware will not do its check network calls if the device is currently watering. I think Ray can confirm this but do the delays correlate to your station run times?
Update: Technically speaking a lack of pings isn’t an issue as the controller won’t act on this and the network settings won’t change allowing connectivity to remain. Is this correct?
If so, the “new” 2.1.4 should fix the DHCP issue and completely resolve the connecting issue moving forward.