Connection drops every 30 minutes, DHCP issue?

I've been fighting an issue I've been having where my router (Netgear XR500) is losing connection momentarily every 30 minutes on the dot. Picked up a Netgear RAX75 to see if it's doing it as well, and it's not, so I'm trying to figure out why only the XR500 is losing connection. From what I understand over in the Netgear forum, it may have something to do with how Cox is handling the DHCP lease. Since it's happening every 30 minutes, it appears Cox has a 1 hour lease so the router would be asking to renew every 30 minutes. Maybe the XR is more sensitive to the renewal since it's the only one losing connection for a few seconds while it happens, while the RAX75 doesn't? Is this something I can get Cox to fix on their end?

Should note the routers are behind a self-purchased Arris SB8200 on Cox's Gigablast plan.