IPV4 Failover with IPV6

[mloiterman]

I have two WANs:

1. WAN1: Comcast - IPv4 and IPv6
2. WAN2: ATT - IPv4

My LAN firewall rules (in this order):

1. IPv4: WAN1 Failover to WAN2
2. IPv6: WAN1

The problem that I have is that when WAN1 goes down (which happens more frequently than I like), IPv4 traffic fails over nicely to WAN2, but IPv6 traffic gets stuck trying to go out a dead connection.

How can I failover so that IPv4 traffic goes out WAN2 and IPv6 traffic reverts to IPv4 so that it will go out the failover WAN2?

I do not currently have State Killing on Gateway Failure checked off, so states are preserved when the gateway goes down. I thought about using that, but won't that kill all LAN connections that have to go through the router. For example SSH sessions across subnets?