Ongoing static ipv6 issues

I have a Netgear CG3000DCR that worked fine with the old ipv6 setup, but ipv6 has not been working since the static addresses were rolled out in my location.  I've had 3 different CR tickets opened and even had a truck roll to my location to check the modem and the tech said it wasn't an issue on my side.

One of the difficulties in troubleshooting this problem is when I call into tech support, they log into the modem and run a ping test and ipv6 works fine.  They just don't get it that the ping test only uses the WAN ipv6 address (which works fine) and not the LAN ipv6 address (which doesn't work) when the ping test is done from the modem. So there's no way to show its a routing issue on the static assigned LAN /56.

Anyone know how to work around this issue with the WAN ipv6 address working normally but there's no way to show the LAN ipv6 addresses are not working?  Do other models of modem have better debugging tools?