OK, I lied, another update:
At 10:29, 1.5 hrs after the last burst, the DHCP requests started again only this time they did NOT stop in 1 minute. I stopped logging at 11:27 because the rate can be as high a 6 requests per second.
If I don’t hear any back in ~30 mins, I’m going to restart the controller with a static IP address and watch its behavior.