RAX40 only connects via IPv6

Hello,

I have the RAX40 v1.  When it reboots I can see that it successfully gets an ipv4 address from my modem (Arris - Spectrum internet), but my connected devices can only communicate via ipv6.  I will typically start a ping to yahoo and it responds on ipv6 with no issues, but if I direct it to ipv4 it dies.  The router shows an ipv4 address from the modem.

I am currently on Firmware 1.0.3.88_1.0.1, but I have had the same issue on 1.0.3.80_1.0.1.

Troubleshooting I have tried:

Disabling ipv6 on the router, rebooting - same issue.

Release/renew address from router to cable modem - same issue.

Change ipv4 DNS providers on router (typically use 8.8.8.8 and 9.9.9.9, but have tried using Spectrum's automatically provided DNS) - same issue.

Have tried multiple devices (I have roughly 20 connected - Windows 10, android, samsung tvs, rokus, etc) - all have the same issue.

Have tried plugging in directly to the router - same issue.

IPv6 capable web pages (yahoo.com for example) work perfectly fine.

I have rebooted the modem and router multiple times - both physically and virtually - same issues.

There is nothing in the logs that seems to alert me to a DNS issue or an IPv4 issue from Spectrum.

After an indeterminate amount of time - usually somewhere from 15 minutes to 45 minutes - ipv4 eventually starts working with everything connected.

Thoughts?