19.1 Prod upgrade in Xen VM w/ AT&T fiber - WAN IP conflict

[jcdick1]

I upgraded from 18.7 to 19.1, and now I am getting this in the logs:

Feb 1 14:26:00   kernel: arp: mm:aa:cc:aa:dd:rr is using my IP address XX.XX.XX.XX on xn3!
Feb 1 14:25:59   kernel: arp: mm:aa:cc:aa:dd:rr is using my IP address XX.XX.XX.XX on xn3!
Feb 1 14:25:58   kernel: arp: mm:aa:cc:aa:dd:rr is using my IP address XX.XX.XX.XX on xn3!
Feb 1 14:25:55   kernel: arp: mm:aa:cc:aa:dd:rr is using my IP address XX.XX.XX.XX on xn3!
Feb 1 14:25:54   kernel: arp: mm:aa:cc:aa:dd:rr is using my IP address XX.XX.XX.XX on xn3!

With AT&T fiber, the router provided by them is required, as it does some sort of authentication and acts as the filter for TV signals over the fiber.  However, it can be configured for a "passthrough" for a host behind it to receive the public IP.  That MAC address is the AT&T box and the IP is the public IP address.  It was fine under 18.7 but now the network is pretty slow, I'm guessing due to the conflict.

The only thing I've changed is the upgrade.

Any ideas would be appreciated.