I have some additional observations. It appears that the thread border router disconnects from WiFi but remains active as the primary thread router. This indicating that the issue is the crashing and disconnecting without reconnecting to wifi. Does this help anybody in the direction that I should ...

I too am experiencing a similar issue. It's almost as off the device crashes. This happens for both the Ethernet version I have as well as several wireless versions I have made. Also it happens so infrequently it's hard to pinpoint. Any help would be appreciated.