Cannot ping Comcast gateway IP after maintenance outage

Hello,

I experienced a problem this morning after a planned Xfinity maintenance outage. After the outage, I rebooted the Modem and my router pulled a new WAN IP address (DHCP), however, the IPv4 Gateway monitor in my router was showing 100% loss and I could not get out to the internet via IPv4.

The IPv6 interface, however, seemed to be working fine.

Looking at the router logs I noticed this message repeating many times:

Sep 16 05:38:00 	kernel 		arpresolve: can't allocate llinfo for 71.226.124.1 on igb0

I attempted to ping the Comcast GW (71.226.124.1) from my phone via LTE but got 100% packet loss result.

Does this mean the Comcast gateway is down?

Investigating further, I looked at the router: Status/Interfaces/WAN and observed that Comcast has me allocated on a /22 subnet. So I manually changed the Gateway monitor IP in my router to 71.226.126.1 which is on the same /24 block as my WAN IP.

Now the gateway monitor is green (no packet loss) and I can access the internet via IPv4.

Looking at the router logs again, I am periodically seeing this message:

/interfaces.php: Removing static route for monitor 71.226.126.1 and adding a new route through 71.226.124.1

Should I call Comcast/Xfinity and get a trouble ticket started?

BTW - also posted this question on the Netgate forums:

https://forum.netgate.com/topic/161391/arpresolve-can-t-allocate-llinfo-for-gw_ip-on-igb0